Develop Reference

How to use bracket notation to access model property inside the loop in c# [duplicate]

I am trying implement the Data transformation using Reflection1 example in my code.
The GetSourceValue function has a switch comparing various types, but I want to remove these types and properties and have GetSourceValue get the value of the property using only a single string as the parameter. I want to pass a class and property in the string and resolve the value of the property.
Is this possible?
1 Web Archive version of original blog post

public static object GetPropValue(object src, string propName)
{
return src.GetType().GetProperty(propName).GetValue(src, null);
}
Of course, you will want to add validation and whatnot, but that is the gist of it.

How about something like this:
public static Object GetPropValue(this Object obj, String name) {
foreach (String part in name.Split('.')) {
if (obj == null) { return null; }
Type type = obj.GetType();
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
return obj;
}
public static T GetPropValue<T>(this Object obj, String name) {
Object retval = GetPropValue(obj, name);
if (retval == null) { return default(T); }
// throws InvalidCastException if types are incompatible
return (T) retval;
}
This will allow you to descend into properties using a single string, like this:
DateTime now = DateTime.Now;
int min = GetPropValue<int>(now, "TimeOfDay.Minutes");
int hrs = now.GetPropValue<int>("TimeOfDay.Hours");
You can either use these methods as static methods or extensions.

Add to any Class:
public class Foo
{
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
public string Bar { get; set; }
}
Then, you can use as:
Foo f = new Foo();
// Set
f["Bar"] = "asdf";
// Get
string s = (string)f["Bar"];

What about using the CallByName of the Microsoft.VisualBasic namespace (Microsoft.VisualBasic.dll)? It uses reflection to get properties, fields, and methods of normal objects, COM objects, and even dynamic objects.
using Microsoft.VisualBasic;
using Microsoft.VisualBasic.CompilerServices;
and then
Versioned.CallByName(this, "method/function/prop name", CallType.Get).ToString();

Great answer by jheddings. I would like to improve it by allowing referencing of aggregated arrays or collections of objects, so that propertyName could be property1.property2[X].property3:
public static object GetPropertyValue(object srcobj, string propertyName)
{
if (srcobj == null)
return null;
object obj = srcobj;
// Split property name to parts (propertyName could be hierarchical, like obj.subobj.subobj.property
string[] propertyNameParts = propertyName.Split('.');
foreach (string propertyNamePart in propertyNameParts)
{
if (obj == null) return null;
// propertyNamePart could contain reference to specific
// element (by index) inside a collection
if (!propertyNamePart.Contains("["))
{
PropertyInfo pi = obj.GetType().GetProperty(propertyNamePart);
if (pi == null) return null;
obj = pi.GetValue(obj, null);
}
else
{ // propertyNamePart is areference to specific element
// (by index) inside a collection
// like AggregatedCollection[123]
// get collection name and element index
int indexStart = propertyNamePart.IndexOf("[")+1;
string collectionPropertyName = propertyNamePart.Substring(0, indexStart-1);
int collectionElementIndex = Int32.Parse(propertyNamePart.Substring(indexStart, propertyNamePart.Length-indexStart-1));
// get collection object
PropertyInfo pi = obj.GetType().GetProperty(collectionPropertyName);
if (pi == null) return null;
object unknownCollection = pi.GetValue(obj, null);
// try to process the collection as array
if (unknownCollection.GetType().IsArray)
{
object[] collectionAsArray = unknownCollection as object[];
obj = collectionAsArray[collectionElementIndex];
}
else
{
// try to process the collection as IList
System.Collections.IList collectionAsList = unknownCollection as System.Collections.IList;
if (collectionAsList != null)
{
obj = collectionAsList[collectionElementIndex];
}
else
{
// ??? Unsupported collection type
}
}
}
}
return obj;
}

If I use the code from Ed S. I get
'ReflectionExtensions.GetProperty(Type, string)' is inaccessible due to its protection level
It seems that GetProperty() is not available in Xamarin.Forms. TargetFrameworkProfile is Profile7 in my Portable Class Library (.NET Framework 4.5, Windows 8, ASP.NET Core 1.0, Xamarin.Android, Xamarin.iOS, Xamarin.iOS Classic).
Now I found a working solution:
using System.Linq;
using System.Reflection;
public static object GetPropValue(object source, string propertyName)
{
var property = source.GetType().GetRuntimeProperties().FirstOrDefault(p => string.Equals(p.Name, propertyName, StringComparison.OrdinalIgnoreCase));
return property?.GetValue(source);
}
Source

About the nested properties discussion, you can avoid all the reflection stuff if you use the DataBinder.Eval Method (Object, String) as below:
var value = DataBinder.Eval(DateTime.Now, "TimeOfDay.Hours");
Of course, you'll need to add a reference to the System.Web assembly, but this probably isn't a big deal.

The method to call has changed in .NET Standard (as of 1.6). Also we can use C# 6's null conditional operator.
using System.Reflection;
public static object GetPropValue(object src, string propName)
{
return src.GetType().GetRuntimeProperty(propName)?.GetValue(src);
}

The below method works perfect for me:
class MyClass {
public string prop1 { set; get; }
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
}
To get the property value:
MyClass t1 = new MyClass();
...
string value = t1["prop1"].ToString();
To set the property value:
t1["prop1"] = value;

public static List<KeyValuePair<string, string>> GetProperties(object item) //where T : class
{
var result = new List<KeyValuePair<string, string>>();
if (item != null)
{
var type = item.GetType();
var properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (var pi in properties)
{
var selfValue = type.GetProperty(pi.Name).GetValue(item, null);
if (selfValue != null)
{
result.Add(new KeyValuePair<string, string>(pi.Name, selfValue.ToString()));
}
else
{
result.Add(new KeyValuePair<string, string>(pi.Name, null));
}
}
}
return result;
}
This is a way to get all properties with their values in a List.

Using PropertyInfo of the System.Reflection namespace. Reflection compiles just fine no matter what property we try to access. The error will come up during run-time.
public static object GetObjProperty(object obj, string property)
{
Type t = obj.GetType();
PropertyInfo p = t.GetProperty("Location");
Point location = (Point)p.GetValue(obj, null);
return location;
}
It works fine to get the Location property of an object
Label1.Text = GetObjProperty(button1, "Location").ToString();
We'll get the Location : {X=71,Y=27}
We can also return location.X or location.Y on the same way.

public class YourClass
{
//Add below line in your class
public object this[string propertyName] => GetType().GetProperty(propertyName)?.GetValue(this, null);
public string SampleProperty { get; set; }
}
//And you can get value of any property like this.
var value = YourClass["SampleProperty"];

The following code is a Recursive method for displaying the entire hierarchy of all of the Property Names and Values contained in an object's instance. This method uses a simplified version of AlexD's GetPropertyValue() answer above in this thread. Thanks to this discussion thread, I was able to figure out how to do this!
For example, I use this method to show an explosion or dump of all of the properties in a WebService response by calling the method as follows:
PropertyValues_byRecursion("Response", response, false);
public static object GetPropertyValue(object srcObj, string propertyName)
{
if (srcObj == null)
{
return null;
}
PropertyInfo pi = srcObj.GetType().GetProperty(propertyName.Replace("[]", ""));
if (pi == null)
{
return null;
}
return pi.GetValue(srcObj);
}
public static void PropertyValues_byRecursion(string parentPath, object parentObj, bool showNullValues)
{
/// Processes all of the objects contained in the parent object.
/// If an object has a Property Value, then the value is written to the Console
/// Else if the object is a container, then this method is called recursively
/// using the current path and current object as parameters
// Note: If you do not want to see null values, set showNullValues = false
foreach (PropertyInfo pi in parentObj.GetType().GetTypeInfo().GetProperties())
{
// Build the current object property's namespace path.
// Recursion extends this to be the property's full namespace path.
string currentPath = parentPath + "." + pi.Name;
// Get the selected property's value as an object
object myPropertyValue = GetPropertyValue(parentObj, pi.Name);
if (myPropertyValue == null)
{
// Instance of Property does not exist
if (showNullValues)
{
Console.WriteLine(currentPath + " = null");
// Note: If you are replacing these Console.Write... methods callback methods,
// consider passing DBNull.Value instead of null in any method object parameters.
}
}
else if (myPropertyValue.GetType().IsArray)
{
// myPropertyValue is an object instance of an Array of business objects.
// Initialize an array index variable so we can show NamespacePath[idx] in the results.
int idx = 0;
foreach (object business in (Array)myPropertyValue)
{
if (business == null)
{
// Instance of Property does not exist
// Not sure if this is possible in this context.
if (showNullValues)
{
Console.WriteLine(currentPath + "[" + idx.ToString() + "]" + " = null");
}
}
else if (business.GetType().IsArray)
{
// myPropertyValue[idx] is another Array!
// Let recursion process it.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
else if (business.GetType().IsSealed)
{
// Display the Full Property Path and its Value
Console.WriteLine(currentPath + "[" + idx.ToString() + "] = " + business.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
idx++;
}
}
else if (myPropertyValue.GetType().IsSealed)
{
// myPropertyValue is a simple value
Console.WriteLine(currentPath + " = " + myPropertyValue.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath, myPropertyValue, showNullValues);
}
}
}

public static TValue GetFieldValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetFields(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.FieldType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}
public static TValue GetPropertyValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetProperties(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.PropertyType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}

Dim NewHandle As YourType = CType(Microsoft.VisualBasic.CallByName(ObjectThatContainsYourVariable, "YourVariableName", CallType), YourType)

Here is another way to find a nested property that doesn't require the string to tell you the nesting path. Credit to Ed S. for the single property method.
public static T FindNestedPropertyValue<T, N>(N model, string propName) {
T retVal = default(T);
bool found = false;
PropertyInfo[] properties = typeof(N).GetProperties();
foreach (PropertyInfo property in properties) {
var currentProperty = property.GetValue(model, null);
if (!found) {
try {
retVal = GetPropValue<T>(currentProperty, propName);
found = true;
} catch { }
}
}
if (!found) {
throw new Exception("Unable to find property: " + propName);
}
return retVal;
}
public static T GetPropValue<T>(object srcObject, string propName) {
return (T)srcObject.GetType().GetProperty(propName).GetValue(srcObject, null);
}

You never mention what object you are inspecting, and since you are rejecting ones that reference a given object, I will assume you mean a static one.
using System.Reflection;
public object GetPropValue(string prop)
{
int splitPoint = prop.LastIndexOf('.');
Type type = Assembly.GetEntryAssembly().GetType(prop.Substring(0, splitPoint));
object obj = null;
return type.GetProperty(prop.Substring(splitPoint + 1)).GetValue(obj, null);
}
Note that I marked the object that is being inspected with the local variable obj. null means static, otherwise set it to what you want. Also note that the GetEntryAssembly() is one of a few available methods to get the "running" assembly, you may want to play around with it if you are having a hard time loading the type.

Have a look at the Heleonix.Reflection library. You can get/set/invoke members by paths, or create a getter/setter (lambda compiled into a delegate) which is faster than reflection. For example:
var success = Reflector.Get(DateTime.Now, null, "Date.Year", out int value);
Or create a getter once and cache for reuse (this is more performant but might throw NullReferenceException if an intermediate member is null):
var getter = Reflector.CreateGetter<DateTime, int>("Date.Year", typeof(DateTime));
getter(DateTime.Now);
Or if you want to create a List<Action<object, object>> of different getters, just specify base types for compiled delegates (type conversions will be added into compiled lambdas):
var getter = Reflector.CreateGetter<object, object>("Date.Year", typeof(DateTime));
getter(DateTime.Now);

Although the original question was about how to get the value of the property using only a single string as the parameter, it makes a lot of sense here to use an Expression rather than simply a string to ensure that the caller never uses a hard coded property name. Here is a one line version with usage:
public static class Utils
...
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
=> (TVal)((x.Body as MemberExpression)?.Member as PropertyInfo)!.GetValue(t);
...
var val = Utils.GetPropertyValue(foo, p => p.Bar);
Here is a slightly better version in terms of readability a error handling:
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
{
var m = (x.Body as MemberExpression)?.Member;
var p = m as PropertyInfo;
if (null == p)
throw new ArgumentException($"Unknown property: {typeof(T).Name}.{(m?.Name??"???")}");
return (TVal)p.GetValue(t);
}
In short you pass in a lambda expression reading a property. The body of the lambda - the part on the right of the fat arrow - is a member expression from which you can get the member name and which you can cast to a PropertyInfo, provided the member is actually a Property and not, for instance, a method.
In the short version, the null forgiving operator - the ! in the expression - tells the compiler that the PropertyInfo will not be null. This is a big lie and you will get a NullReferenceException at runtime. The longer version gives you the name of the property if it manages to get it.
PS: Thanks to Oleg G. for the initial version of this code :)

shorter way ....
var a = new Test { Id = 1 , Name = "A" , date = DateTime.Now};
var b = new Test { Id = 1 , Name = "AXXX", date = DateTime.Now };
var compare = string.Join("",a.GetType().GetProperties().Select(x => x.GetValue(a)).ToArray())==
string.Join("",b.GetType().GetProperties().Select(x => x.GetValue(b)).ToArray());

jheddings and AlexD both wrote excellent answers on how to resolve property strings. I'd like to throw mine in the mix, since I wrote a dedicated library exactly for that purpose.
Pather.CSharp's main class is Resolver. Per default it can resolve properties, array and dictionary entries.
So, for example, if you have an object like this
var o = new { Property1 = new { Property2 = "value" } };
and want to get Property2, you can do it like this:
IResolver resolver = new Resolver();
var path = "Property1.Property2";
object result = r.Resolve(o, path);
//=> "value"
This is the most basic example of the paths it can resolve. If you want to see what else it can, or how you can extend it, just head to its Github page.

Here's what I got based on other answers. A little overkill on getting so specific with the error handling.
public static T GetPropertyValue<T>(object sourceInstance, string targetPropertyName, bool throwExceptionIfNotExists = false)
{
string errorMsg = null;
try
{
if (sourceInstance == null || string.IsNullOrWhiteSpace(targetPropertyName))
{
errorMsg = $"Source object is null or property name is null or whitespace. '{targetPropertyName}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
Type returnType = typeof(T);
Type sourceType = sourceInstance.GetType();
PropertyInfo propertyInfo = sourceType.GetProperty(targetPropertyName, returnType);
if (propertyInfo == null)
{
errorMsg = $"Property name '{targetPropertyName}' of type '{returnType}' not found for source object of type '{sourceType}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
return (T)propertyInfo.GetValue(sourceInstance, null);
}
catch(Exception ex)
{
errorMsg = $"Problem getting property name '{targetPropertyName}' from source instance.";
Log.Error(errorMsg, ex);
if (throwExceptionIfNotExists)
throw;
}
return default(T);
}

Here is my solution. It works also with COM objects and allows to access collection/array items from COM objects.
public static object GetPropValue(this object obj, string name)
{
foreach (string part in name.Split('.'))
{
if (obj == null) { return null; }
Type type = obj.GetType();
if (type.Name == "__ComObject")
{
if (part.Contains('['))
{
string partWithoundIndex = part;
int index = ParseIndexFromPropertyName(ref partWithoundIndex);
obj = Versioned.CallByName(obj, partWithoundIndex, CallType.Get, index);
}
else
{
obj = Versioned.CallByName(obj, part, CallType.Get);
}
}
else
{
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
}
return obj;
}
private static int ParseIndexFromPropertyName(ref string name)
{
int index = -1;
int s = name.IndexOf('[') + 1;
int e = name.IndexOf(']');
if (e < s)
{
throw new ArgumentException();
}
string tmp = name.Substring(s, e - s);
index = Convert.ToInt32(tmp);
name = name.Substring(0, s - 1);
return index;
}

Whenever you want to loop over all properties in on an object and then use each value of the property must use this piece of code:
foreach (var property in request.GetType().GetProperties())
{
var valueOfProperty = property.GetValue(properties, null);
}

How to access property of object with a variable name [duplicate]

I am trying implement the Data transformation using Reflection1 example in my code.
The GetSourceValue function has a switch comparing various types, but I want to remove these types and properties and have GetSourceValue get the value of the property using only a single string as the parameter. I want to pass a class and property in the string and resolve the value of the property.
Is this possible?
1 Web Archive version of original blog post

public static object GetPropValue(object src, string propName)
{
return src.GetType().GetProperty(propName).GetValue(src, null);
}
Of course, you will want to add validation and whatnot, but that is the gist of it.

How about something like this:
public static Object GetPropValue(this Object obj, String name) {
foreach (String part in name.Split('.')) {
if (obj == null) { return null; }
Type type = obj.GetType();
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
return obj;
}
public static T GetPropValue<T>(this Object obj, String name) {
Object retval = GetPropValue(obj, name);
if (retval == null) { return default(T); }
// throws InvalidCastException if types are incompatible
return (T) retval;
}
This will allow you to descend into properties using a single string, like this:
DateTime now = DateTime.Now;
int min = GetPropValue<int>(now, "TimeOfDay.Minutes");
int hrs = now.GetPropValue<int>("TimeOfDay.Hours");
You can either use these methods as static methods or extensions.

Add to any Class:
public class Foo
{
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
public string Bar { get; set; }
}
Then, you can use as:
Foo f = new Foo();
// Set
f["Bar"] = "asdf";
// Get
string s = (string)f["Bar"];

What about using the CallByName of the Microsoft.VisualBasic namespace (Microsoft.VisualBasic.dll)? It uses reflection to get properties, fields, and methods of normal objects, COM objects, and even dynamic objects.
using Microsoft.VisualBasic;
using Microsoft.VisualBasic.CompilerServices;
and then
Versioned.CallByName(this, "method/function/prop name", CallType.Get).ToString();

Great answer by jheddings. I would like to improve it by allowing referencing of aggregated arrays or collections of objects, so that propertyName could be property1.property2[X].property3:
public static object GetPropertyValue(object srcobj, string propertyName)
{
if (srcobj == null)
return null;
object obj = srcobj;
// Split property name to parts (propertyName could be hierarchical, like obj.subobj.subobj.property
string[] propertyNameParts = propertyName.Split('.');
foreach (string propertyNamePart in propertyNameParts)
{
if (obj == null) return null;
// propertyNamePart could contain reference to specific
// element (by index) inside a collection
if (!propertyNamePart.Contains("["))
{
PropertyInfo pi = obj.GetType().GetProperty(propertyNamePart);
if (pi == null) return null;
obj = pi.GetValue(obj, null);
}
else
{ // propertyNamePart is areference to specific element
// (by index) inside a collection
// like AggregatedCollection[123]
// get collection name and element index
int indexStart = propertyNamePart.IndexOf("[")+1;
string collectionPropertyName = propertyNamePart.Substring(0, indexStart-1);
int collectionElementIndex = Int32.Parse(propertyNamePart.Substring(indexStart, propertyNamePart.Length-indexStart-1));
// get collection object
PropertyInfo pi = obj.GetType().GetProperty(collectionPropertyName);
if (pi == null) return null;
object unknownCollection = pi.GetValue(obj, null);
// try to process the collection as array
if (unknownCollection.GetType().IsArray)
{
object[] collectionAsArray = unknownCollection as object[];
obj = collectionAsArray[collectionElementIndex];
}
else
{
// try to process the collection as IList
System.Collections.IList collectionAsList = unknownCollection as System.Collections.IList;
if (collectionAsList != null)
{
obj = collectionAsList[collectionElementIndex];
}
else
{
// ??? Unsupported collection type
}
}
}
}
return obj;
}

If I use the code from Ed S. I get
'ReflectionExtensions.GetProperty(Type, string)' is inaccessible due to its protection level
It seems that GetProperty() is not available in Xamarin.Forms. TargetFrameworkProfile is Profile7 in my Portable Class Library (.NET Framework 4.5, Windows 8, ASP.NET Core 1.0, Xamarin.Android, Xamarin.iOS, Xamarin.iOS Classic).
Now I found a working solution:
using System.Linq;
using System.Reflection;
public static object GetPropValue(object source, string propertyName)
{
var property = source.GetType().GetRuntimeProperties().FirstOrDefault(p => string.Equals(p.Name, propertyName, StringComparison.OrdinalIgnoreCase));
return property?.GetValue(source);
}
Source

About the nested properties discussion, you can avoid all the reflection stuff if you use the DataBinder.Eval Method (Object, String) as below:
var value = DataBinder.Eval(DateTime.Now, "TimeOfDay.Hours");
Of course, you'll need to add a reference to the System.Web assembly, but this probably isn't a big deal.

The method to call has changed in .NET Standard (as of 1.6). Also we can use C# 6's null conditional operator.
using System.Reflection;
public static object GetPropValue(object src, string propName)
{
return src.GetType().GetRuntimeProperty(propName)?.GetValue(src);
}

The below method works perfect for me:
class MyClass {
public string prop1 { set; get; }
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
}
To get the property value:
MyClass t1 = new MyClass();
...
string value = t1["prop1"].ToString();
To set the property value:
t1["prop1"] = value;

public static List<KeyValuePair<string, string>> GetProperties(object item) //where T : class
{
var result = new List<KeyValuePair<string, string>>();
if (item != null)
{
var type = item.GetType();
var properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (var pi in properties)
{
var selfValue = type.GetProperty(pi.Name).GetValue(item, null);
if (selfValue != null)
{
result.Add(new KeyValuePair<string, string>(pi.Name, selfValue.ToString()));
}
else
{
result.Add(new KeyValuePair<string, string>(pi.Name, null));
}
}
}
return result;
}
This is a way to get all properties with their values in a List.

Using PropertyInfo of the System.Reflection namespace. Reflection compiles just fine no matter what property we try to access. The error will come up during run-time.
public static object GetObjProperty(object obj, string property)
{
Type t = obj.GetType();
PropertyInfo p = t.GetProperty("Location");
Point location = (Point)p.GetValue(obj, null);
return location;
}
It works fine to get the Location property of an object
Label1.Text = GetObjProperty(button1, "Location").ToString();
We'll get the Location : {X=71,Y=27}
We can also return location.X or location.Y on the same way.

public class YourClass
{
//Add below line in your class
public object this[string propertyName] => GetType().GetProperty(propertyName)?.GetValue(this, null);
public string SampleProperty { get; set; }
}
//And you can get value of any property like this.
var value = YourClass["SampleProperty"];

The following code is a Recursive method for displaying the entire hierarchy of all of the Property Names and Values contained in an object's instance. This method uses a simplified version of AlexD's GetPropertyValue() answer above in this thread. Thanks to this discussion thread, I was able to figure out how to do this!
For example, I use this method to show an explosion or dump of all of the properties in a WebService response by calling the method as follows:
PropertyValues_byRecursion("Response", response, false);
public static object GetPropertyValue(object srcObj, string propertyName)
{
if (srcObj == null)
{
return null;
}
PropertyInfo pi = srcObj.GetType().GetProperty(propertyName.Replace("[]", ""));
if (pi == null)
{
return null;
}
return pi.GetValue(srcObj);
}
public static void PropertyValues_byRecursion(string parentPath, object parentObj, bool showNullValues)
{
/// Processes all of the objects contained in the parent object.
/// If an object has a Property Value, then the value is written to the Console
/// Else if the object is a container, then this method is called recursively
/// using the current path and current object as parameters
// Note: If you do not want to see null values, set showNullValues = false
foreach (PropertyInfo pi in parentObj.GetType().GetTypeInfo().GetProperties())
{
// Build the current object property's namespace path.
// Recursion extends this to be the property's full namespace path.
string currentPath = parentPath + "." + pi.Name;
// Get the selected property's value as an object
object myPropertyValue = GetPropertyValue(parentObj, pi.Name);
if (myPropertyValue == null)
{
// Instance of Property does not exist
if (showNullValues)
{
Console.WriteLine(currentPath + " = null");
// Note: If you are replacing these Console.Write... methods callback methods,
// consider passing DBNull.Value instead of null in any method object parameters.
}
}
else if (myPropertyValue.GetType().IsArray)
{
// myPropertyValue is an object instance of an Array of business objects.
// Initialize an array index variable so we can show NamespacePath[idx] in the results.
int idx = 0;
foreach (object business in (Array)myPropertyValue)
{
if (business == null)
{
// Instance of Property does not exist
// Not sure if this is possible in this context.
if (showNullValues)
{
Console.WriteLine(currentPath + "[" + idx.ToString() + "]" + " = null");
}
}
else if (business.GetType().IsArray)
{
// myPropertyValue[idx] is another Array!
// Let recursion process it.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
else if (business.GetType().IsSealed)
{
// Display the Full Property Path and its Value
Console.WriteLine(currentPath + "[" + idx.ToString() + "] = " + business.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
idx++;
}
}
else if (myPropertyValue.GetType().IsSealed)
{
// myPropertyValue is a simple value
Console.WriteLine(currentPath + " = " + myPropertyValue.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath, myPropertyValue, showNullValues);
}
}
}

public static TValue GetFieldValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetFields(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.FieldType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}
public static TValue GetPropertyValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetProperties(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.PropertyType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}

Dim NewHandle As YourType = CType(Microsoft.VisualBasic.CallByName(ObjectThatContainsYourVariable, "YourVariableName", CallType), YourType)

Here is another way to find a nested property that doesn't require the string to tell you the nesting path. Credit to Ed S. for the single property method.
public static T FindNestedPropertyValue<T, N>(N model, string propName) {
T retVal = default(T);
bool found = false;
PropertyInfo[] properties = typeof(N).GetProperties();
foreach (PropertyInfo property in properties) {
var currentProperty = property.GetValue(model, null);
if (!found) {
try {
retVal = GetPropValue<T>(currentProperty, propName);
found = true;
} catch { }
}
}
if (!found) {
throw new Exception("Unable to find property: " + propName);
}
return retVal;
}
public static T GetPropValue<T>(object srcObject, string propName) {
return (T)srcObject.GetType().GetProperty(propName).GetValue(srcObject, null);
}

You never mention what object you are inspecting, and since you are rejecting ones that reference a given object, I will assume you mean a static one.
using System.Reflection;
public object GetPropValue(string prop)
{
int splitPoint = prop.LastIndexOf('.');
Type type = Assembly.GetEntryAssembly().GetType(prop.Substring(0, splitPoint));
object obj = null;
return type.GetProperty(prop.Substring(splitPoint + 1)).GetValue(obj, null);
}
Note that I marked the object that is being inspected with the local variable obj. null means static, otherwise set it to what you want. Also note that the GetEntryAssembly() is one of a few available methods to get the "running" assembly, you may want to play around with it if you are having a hard time loading the type.

Have a look at the Heleonix.Reflection library. You can get/set/invoke members by paths, or create a getter/setter (lambda compiled into a delegate) which is faster than reflection. For example:
var success = Reflector.Get(DateTime.Now, null, "Date.Year", out int value);
Or create a getter once and cache for reuse (this is more performant but might throw NullReferenceException if an intermediate member is null):
var getter = Reflector.CreateGetter<DateTime, int>("Date.Year", typeof(DateTime));
getter(DateTime.Now);
Or if you want to create a List<Action<object, object>> of different getters, just specify base types for compiled delegates (type conversions will be added into compiled lambdas):
var getter = Reflector.CreateGetter<object, object>("Date.Year", typeof(DateTime));
getter(DateTime.Now);

Although the original question was about how to get the value of the property using only a single string as the parameter, it makes a lot of sense here to use an Expression rather than simply a string to ensure that the caller never uses a hard coded property name. Here is a one line version with usage:
public static class Utils
...
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
=> (TVal)((x.Body as MemberExpression)?.Member as PropertyInfo)!.GetValue(t);
...
var val = Utils.GetPropertyValue(foo, p => p.Bar);
Here is a slightly better version in terms of readability a error handling:
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
{
var m = (x.Body as MemberExpression)?.Member;
var p = m as PropertyInfo;
if (null == p)
throw new ArgumentException($"Unknown property: {typeof(T).Name}.{(m?.Name??"???")}");
return (TVal)p.GetValue(t);
}
In short you pass in a lambda expression reading a property. The body of the lambda - the part on the right of the fat arrow - is a member expression from which you can get the member name and which you can cast to a PropertyInfo, provided the member is actually a Property and not, for instance, a method.
In the short version, the null forgiving operator - the ! in the expression - tells the compiler that the PropertyInfo will not be null. This is a big lie and you will get a NullReferenceException at runtime. The longer version gives you the name of the property if it manages to get it.
PS: Thanks to Oleg G. for the initial version of this code :)

shorter way ....
var a = new Test { Id = 1 , Name = "A" , date = DateTime.Now};
var b = new Test { Id = 1 , Name = "AXXX", date = DateTime.Now };
var compare = string.Join("",a.GetType().GetProperties().Select(x => x.GetValue(a)).ToArray())==
string.Join("",b.GetType().GetProperties().Select(x => x.GetValue(b)).ToArray());

jheddings and AlexD both wrote excellent answers on how to resolve property strings. I'd like to throw mine in the mix, since I wrote a dedicated library exactly for that purpose.
Pather.CSharp's main class is Resolver. Per default it can resolve properties, array and dictionary entries.
So, for example, if you have an object like this
var o = new { Property1 = new { Property2 = "value" } };
and want to get Property2, you can do it like this:
IResolver resolver = new Resolver();
var path = "Property1.Property2";
object result = r.Resolve(o, path);
//=> "value"
This is the most basic example of the paths it can resolve. If you want to see what else it can, or how you can extend it, just head to its Github page.

Here's what I got based on other answers. A little overkill on getting so specific with the error handling.
public static T GetPropertyValue<T>(object sourceInstance, string targetPropertyName, bool throwExceptionIfNotExists = false)
{
string errorMsg = null;
try
{
if (sourceInstance == null || string.IsNullOrWhiteSpace(targetPropertyName))
{
errorMsg = $"Source object is null or property name is null or whitespace. '{targetPropertyName}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
Type returnType = typeof(T);
Type sourceType = sourceInstance.GetType();
PropertyInfo propertyInfo = sourceType.GetProperty(targetPropertyName, returnType);
if (propertyInfo == null)
{
errorMsg = $"Property name '{targetPropertyName}' of type '{returnType}' not found for source object of type '{sourceType}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
return (T)propertyInfo.GetValue(sourceInstance, null);
}
catch(Exception ex)
{
errorMsg = $"Problem getting property name '{targetPropertyName}' from source instance.";
Log.Error(errorMsg, ex);
if (throwExceptionIfNotExists)
throw;
}
return default(T);
}

Here is my solution. It works also with COM objects and allows to access collection/array items from COM objects.
public static object GetPropValue(this object obj, string name)
{
foreach (string part in name.Split('.'))
{
if (obj == null) { return null; }
Type type = obj.GetType();
if (type.Name == "__ComObject")
{
if (part.Contains('['))
{
string partWithoundIndex = part;
int index = ParseIndexFromPropertyName(ref partWithoundIndex);
obj = Versioned.CallByName(obj, partWithoundIndex, CallType.Get, index);
}
else
{
obj = Versioned.CallByName(obj, part, CallType.Get);
}
}
else
{
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
}
return obj;
}
private static int ParseIndexFromPropertyName(ref string name)
{
int index = -1;
int s = name.IndexOf('[') + 1;
int e = name.IndexOf(']');
if (e < s)
{
throw new ArgumentException();
}
string tmp = name.Substring(s, e - s);
index = Convert.ToInt32(tmp);
name = name.Substring(0, s - 1);
return index;
}

Whenever you want to loop over all properties in on an object and then use each value of the property must use this piece of code:
foreach (var property in request.GetType().GetProperties())
{
var valueOfProperty = property.GetValue(properties, null);
}

Enum get value by reference c# [duplicate]

I am trying implement the Data transformation using Reflection1 example in my code.
The GetSourceValue function has a switch comparing various types, but I want to remove these types and properties and have GetSourceValue get the value of the property using only a single string as the parameter. I want to pass a class and property in the string and resolve the value of the property.
Is this possible?
1 Web Archive version of original blog post

public static object GetPropValue(object src, string propName)
{
return src.GetType().GetProperty(propName).GetValue(src, null);
}
Of course, you will want to add validation and whatnot, but that is the gist of it.

How about something like this:
public static Object GetPropValue(this Object obj, String name) {
foreach (String part in name.Split('.')) {
if (obj == null) { return null; }
Type type = obj.GetType();
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
return obj;
}
public static T GetPropValue<T>(this Object obj, String name) {
Object retval = GetPropValue(obj, name);
if (retval == null) { return default(T); }
// throws InvalidCastException if types are incompatible
return (T) retval;
}
This will allow you to descend into properties using a single string, like this:
DateTime now = DateTime.Now;
int min = GetPropValue<int>(now, "TimeOfDay.Minutes");
int hrs = now.GetPropValue<int>("TimeOfDay.Hours");
You can either use these methods as static methods or extensions.

Add to any Class:
public class Foo
{
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
public string Bar { get; set; }
}
Then, you can use as:
Foo f = new Foo();
// Set
f["Bar"] = "asdf";
// Get
string s = (string)f["Bar"];

What about using the CallByName of the Microsoft.VisualBasic namespace (Microsoft.VisualBasic.dll)? It uses reflection to get properties, fields, and methods of normal objects, COM objects, and even dynamic objects.
using Microsoft.VisualBasic;
using Microsoft.VisualBasic.CompilerServices;
and then
Versioned.CallByName(this, "method/function/prop name", CallType.Get).ToString();

Great answer by jheddings. I would like to improve it by allowing referencing of aggregated arrays or collections of objects, so that propertyName could be property1.property2[X].property3:
public static object GetPropertyValue(object srcobj, string propertyName)
{
if (srcobj == null)
return null;
object obj = srcobj;
// Split property name to parts (propertyName could be hierarchical, like obj.subobj.subobj.property
string[] propertyNameParts = propertyName.Split('.');
foreach (string propertyNamePart in propertyNameParts)
{
if (obj == null) return null;
// propertyNamePart could contain reference to specific
// element (by index) inside a collection
if (!propertyNamePart.Contains("["))
{
PropertyInfo pi = obj.GetType().GetProperty(propertyNamePart);
if (pi == null) return null;
obj = pi.GetValue(obj, null);
}
else
{ // propertyNamePart is areference to specific element
// (by index) inside a collection
// like AggregatedCollection[123]
// get collection name and element index
int indexStart = propertyNamePart.IndexOf("[")+1;
string collectionPropertyName = propertyNamePart.Substring(0, indexStart-1);
int collectionElementIndex = Int32.Parse(propertyNamePart.Substring(indexStart, propertyNamePart.Length-indexStart-1));
// get collection object
PropertyInfo pi = obj.GetType().GetProperty(collectionPropertyName);
if (pi == null) return null;
object unknownCollection = pi.GetValue(obj, null);
// try to process the collection as array
if (unknownCollection.GetType().IsArray)
{
object[] collectionAsArray = unknownCollection as object[];
obj = collectionAsArray[collectionElementIndex];
}
else
{
// try to process the collection as IList
System.Collections.IList collectionAsList = unknownCollection as System.Collections.IList;
if (collectionAsList != null)
{
obj = collectionAsList[collectionElementIndex];
}
else
{
// ??? Unsupported collection type
}
}
}
}
return obj;
}

If I use the code from Ed S. I get
'ReflectionExtensions.GetProperty(Type, string)' is inaccessible due to its protection level
It seems that GetProperty() is not available in Xamarin.Forms. TargetFrameworkProfile is Profile7 in my Portable Class Library (.NET Framework 4.5, Windows 8, ASP.NET Core 1.0, Xamarin.Android, Xamarin.iOS, Xamarin.iOS Classic).
Now I found a working solution:
using System.Linq;
using System.Reflection;
public static object GetPropValue(object source, string propertyName)
{
var property = source.GetType().GetRuntimeProperties().FirstOrDefault(p => string.Equals(p.Name, propertyName, StringComparison.OrdinalIgnoreCase));
return property?.GetValue(source);
}
Source

About the nested properties discussion, you can avoid all the reflection stuff if you use the DataBinder.Eval Method (Object, String) as below:
var value = DataBinder.Eval(DateTime.Now, "TimeOfDay.Hours");
Of course, you'll need to add a reference to the System.Web assembly, but this probably isn't a big deal.

The method to call has changed in .NET Standard (as of 1.6). Also we can use C# 6's null conditional operator.
using System.Reflection;
public static object GetPropValue(object src, string propName)
{
return src.GetType().GetRuntimeProperty(propName)?.GetValue(src);
}

The below method works perfect for me:
class MyClass {
public string prop1 { set; get; }
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
}
To get the property value:
MyClass t1 = new MyClass();
...
string value = t1["prop1"].ToString();
To set the property value:
t1["prop1"] = value;

public static List<KeyValuePair<string, string>> GetProperties(object item) //where T : class
{
var result = new List<KeyValuePair<string, string>>();
if (item != null)
{
var type = item.GetType();
var properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (var pi in properties)
{
var selfValue = type.GetProperty(pi.Name).GetValue(item, null);
if (selfValue != null)
{
result.Add(new KeyValuePair<string, string>(pi.Name, selfValue.ToString()));
}
else
{
result.Add(new KeyValuePair<string, string>(pi.Name, null));
}
}
}
return result;
}
This is a way to get all properties with their values in a List.

Using PropertyInfo of the System.Reflection namespace. Reflection compiles just fine no matter what property we try to access. The error will come up during run-time.
public static object GetObjProperty(object obj, string property)
{
Type t = obj.GetType();
PropertyInfo p = t.GetProperty("Location");
Point location = (Point)p.GetValue(obj, null);
return location;
}
It works fine to get the Location property of an object
Label1.Text = GetObjProperty(button1, "Location").ToString();
We'll get the Location : {X=71,Y=27}
We can also return location.X or location.Y on the same way.

public class YourClass
{
//Add below line in your class
public object this[string propertyName] => GetType().GetProperty(propertyName)?.GetValue(this, null);
public string SampleProperty { get; set; }
}
//And you can get value of any property like this.
var value = YourClass["SampleProperty"];

The following code is a Recursive method for displaying the entire hierarchy of all of the Property Names and Values contained in an object's instance. This method uses a simplified version of AlexD's GetPropertyValue() answer above in this thread. Thanks to this discussion thread, I was able to figure out how to do this!
For example, I use this method to show an explosion or dump of all of the properties in a WebService response by calling the method as follows:
PropertyValues_byRecursion("Response", response, false);
public static object GetPropertyValue(object srcObj, string propertyName)
{
if (srcObj == null)
{
return null;
}
PropertyInfo pi = srcObj.GetType().GetProperty(propertyName.Replace("[]", ""));
if (pi == null)
{
return null;
}
return pi.GetValue(srcObj);
}
public static void PropertyValues_byRecursion(string parentPath, object parentObj, bool showNullValues)
{
/// Processes all of the objects contained in the parent object.
/// If an object has a Property Value, then the value is written to the Console
/// Else if the object is a container, then this method is called recursively
/// using the current path and current object as parameters
// Note: If you do not want to see null values, set showNullValues = false
foreach (PropertyInfo pi in parentObj.GetType().GetTypeInfo().GetProperties())
{
// Build the current object property's namespace path.
// Recursion extends this to be the property's full namespace path.
string currentPath = parentPath + "." + pi.Name;
// Get the selected property's value as an object
object myPropertyValue = GetPropertyValue(parentObj, pi.Name);
if (myPropertyValue == null)
{
// Instance of Property does not exist
if (showNullValues)
{
Console.WriteLine(currentPath + " = null");
// Note: If you are replacing these Console.Write... methods callback methods,
// consider passing DBNull.Value instead of null in any method object parameters.
}
}
else if (myPropertyValue.GetType().IsArray)
{
// myPropertyValue is an object instance of an Array of business objects.
// Initialize an array index variable so we can show NamespacePath[idx] in the results.
int idx = 0;
foreach (object business in (Array)myPropertyValue)
{
if (business == null)
{
// Instance of Property does not exist
// Not sure if this is possible in this context.
if (showNullValues)
{
Console.WriteLine(currentPath + "[" + idx.ToString() + "]" + " = null");
}
}
else if (business.GetType().IsArray)
{
// myPropertyValue[idx] is another Array!
// Let recursion process it.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
else if (business.GetType().IsSealed)
{
// Display the Full Property Path and its Value
Console.WriteLine(currentPath + "[" + idx.ToString() + "] = " + business.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
idx++;
}
}
else if (myPropertyValue.GetType().IsSealed)
{
// myPropertyValue is a simple value
Console.WriteLine(currentPath + " = " + myPropertyValue.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath, myPropertyValue, showNullValues);
}
}
}

public static TValue GetFieldValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetFields(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.FieldType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}
public static TValue GetPropertyValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetProperties(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.PropertyType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}

Dim NewHandle As YourType = CType(Microsoft.VisualBasic.CallByName(ObjectThatContainsYourVariable, "YourVariableName", CallType), YourType)

Here is another way to find a nested property that doesn't require the string to tell you the nesting path. Credit to Ed S. for the single property method.
public static T FindNestedPropertyValue<T, N>(N model, string propName) {
T retVal = default(T);
bool found = false;
PropertyInfo[] properties = typeof(N).GetProperties();
foreach (PropertyInfo property in properties) {
var currentProperty = property.GetValue(model, null);
if (!found) {
try {
retVal = GetPropValue<T>(currentProperty, propName);
found = true;
} catch { }
}
}
if (!found) {
throw new Exception("Unable to find property: " + propName);
}
return retVal;
}
public static T GetPropValue<T>(object srcObject, string propName) {
return (T)srcObject.GetType().GetProperty(propName).GetValue(srcObject, null);
}

You never mention what object you are inspecting, and since you are rejecting ones that reference a given object, I will assume you mean a static one.
using System.Reflection;
public object GetPropValue(string prop)
{
int splitPoint = prop.LastIndexOf('.');
Type type = Assembly.GetEntryAssembly().GetType(prop.Substring(0, splitPoint));
object obj = null;
return type.GetProperty(prop.Substring(splitPoint + 1)).GetValue(obj, null);
}
Note that I marked the object that is being inspected with the local variable obj. null means static, otherwise set it to what you want. Also note that the GetEntryAssembly() is one of a few available methods to get the "running" assembly, you may want to play around with it if you are having a hard time loading the type.

Have a look at the Heleonix.Reflection library. You can get/set/invoke members by paths, or create a getter/setter (lambda compiled into a delegate) which is faster than reflection. For example:
var success = Reflector.Get(DateTime.Now, null, "Date.Year", out int value);
Or create a getter once and cache for reuse (this is more performant but might throw NullReferenceException if an intermediate member is null):
var getter = Reflector.CreateGetter<DateTime, int>("Date.Year", typeof(DateTime));
getter(DateTime.Now);
Or if you want to create a List<Action<object, object>> of different getters, just specify base types for compiled delegates (type conversions will be added into compiled lambdas):
var getter = Reflector.CreateGetter<object, object>("Date.Year", typeof(DateTime));
getter(DateTime.Now);

Although the original question was about how to get the value of the property using only a single string as the parameter, it makes a lot of sense here to use an Expression rather than simply a string to ensure that the caller never uses a hard coded property name. Here is a one line version with usage:
public static class Utils
...
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
=> (TVal)((x.Body as MemberExpression)?.Member as PropertyInfo)!.GetValue(t);
...
var val = Utils.GetPropertyValue(foo, p => p.Bar);
Here is a slightly better version in terms of readability a error handling:
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
{
var m = (x.Body as MemberExpression)?.Member;
var p = m as PropertyInfo;
if (null == p)
throw new ArgumentException($"Unknown property: {typeof(T).Name}.{(m?.Name??"???")}");
return (TVal)p.GetValue(t);
}
In short you pass in a lambda expression reading a property. The body of the lambda - the part on the right of the fat arrow - is a member expression from which you can get the member name and which you can cast to a PropertyInfo, provided the member is actually a Property and not, for instance, a method.
In the short version, the null forgiving operator - the ! in the expression - tells the compiler that the PropertyInfo will not be null. This is a big lie and you will get a NullReferenceException at runtime. The longer version gives you the name of the property if it manages to get it.
PS: Thanks to Oleg G. for the initial version of this code :)

shorter way ....
var a = new Test { Id = 1 , Name = "A" , date = DateTime.Now};
var b = new Test { Id = 1 , Name = "AXXX", date = DateTime.Now };
var compare = string.Join("",a.GetType().GetProperties().Select(x => x.GetValue(a)).ToArray())==
string.Join("",b.GetType().GetProperties().Select(x => x.GetValue(b)).ToArray());

jheddings and AlexD both wrote excellent answers on how to resolve property strings. I'd like to throw mine in the mix, since I wrote a dedicated library exactly for that purpose.
Pather.CSharp's main class is Resolver. Per default it can resolve properties, array and dictionary entries.
So, for example, if you have an object like this
var o = new { Property1 = new { Property2 = "value" } };
and want to get Property2, you can do it like this:
IResolver resolver = new Resolver();
var path = "Property1.Property2";
object result = r.Resolve(o, path);
//=> "value"
This is the most basic example of the paths it can resolve. If you want to see what else it can, or how you can extend it, just head to its Github page.

Here's what I got based on other answers. A little overkill on getting so specific with the error handling.
public static T GetPropertyValue<T>(object sourceInstance, string targetPropertyName, bool throwExceptionIfNotExists = false)
{
string errorMsg = null;
try
{
if (sourceInstance == null || string.IsNullOrWhiteSpace(targetPropertyName))
{
errorMsg = $"Source object is null or property name is null or whitespace. '{targetPropertyName}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
Type returnType = typeof(T);
Type sourceType = sourceInstance.GetType();
PropertyInfo propertyInfo = sourceType.GetProperty(targetPropertyName, returnType);
if (propertyInfo == null)
{
errorMsg = $"Property name '{targetPropertyName}' of type '{returnType}' not found for source object of type '{sourceType}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
return (T)propertyInfo.GetValue(sourceInstance, null);
}
catch(Exception ex)
{
errorMsg = $"Problem getting property name '{targetPropertyName}' from source instance.";
Log.Error(errorMsg, ex);
if (throwExceptionIfNotExists)
throw;
}
return default(T);
}

Here is my solution. It works also with COM objects and allows to access collection/array items from COM objects.
public static object GetPropValue(this object obj, string name)
{
foreach (string part in name.Split('.'))
{
if (obj == null) { return null; }
Type type = obj.GetType();
if (type.Name == "__ComObject")
{
if (part.Contains('['))
{
string partWithoundIndex = part;
int index = ParseIndexFromPropertyName(ref partWithoundIndex);
obj = Versioned.CallByName(obj, partWithoundIndex, CallType.Get, index);
}
else
{
obj = Versioned.CallByName(obj, part, CallType.Get);
}
}
else
{
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
}
return obj;
}
private static int ParseIndexFromPropertyName(ref string name)
{
int index = -1;
int s = name.IndexOf('[') + 1;
int e = name.IndexOf(']');
if (e < s)
{
throw new ArgumentException();
}
string tmp = name.Substring(s, e - s);
index = Convert.ToInt32(tmp);
name = name.Substring(0, s - 1);
return index;
}

Whenever you want to loop over all properties in on an object and then use each value of the property must use this piece of code:
foreach (var property in request.GetType().GetProperties())
{
var valueOfProperty = property.GetValue(properties, null);
}

What's the best way to compare all properties of two objects? [duplicate]

I have two complex objects like Object1 and Object2. They have around 5 levels of child objects.
I need the fastest method to say if they are same or not.
How could this be done in C# 4.0?

Implement IEquatable<T> (typically in conjunction with overriding the inherited Object.Equals and Object.GetHashCode methods) on all your custom types. In the case of composite types, invoke the contained types’ Equals method within the containing types. For contained collections, use the SequenceEqual extension method, which internally calls IEquatable<T>.Equals or Object.Equals on each element. This approach will obviously require you to extend your types’ definitions, but its results are faster than any generic solutions involving serialization.
Edit: Here is a contrived example with three levels of nesting.
For value types, you can typically just call their Equals method. Even if the fields or properties were never explicitly assigned, they would still have a default value.
For reference types, you should first call ReferenceEquals, which checks for reference equality – this would serve as an efficiency boost when you happen to be referencing the same object. It would also handle cases where both references are null. If that check fails, confirm that your instance's field or property is not null (to avoid NullReferenceException) and call its Equals method. Since our members are properly typed, the IEquatable<T>.Equals method gets called directly, bypassing the overridden Object.Equals method (whose execution would be marginally slower due to the type cast).
When you override Object.Equals, you’re also expected to override Object.GetHashCode; I didn’t do so below for the sake of conciseness.
public class Person : IEquatable<Person>
{
public int Age { get; set; }
public string FirstName { get; set; }
public Address Address { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as Person);
}
public bool Equals(Person other)
{
if (other == null)
return false;
return this.Age.Equals(other.Age) &&
(
object.ReferenceEquals(this.FirstName, other.FirstName) ||
this.FirstName != null &&
this.FirstName.Equals(other.FirstName)
) &&
(
object.ReferenceEquals(this.Address, other.Address) ||
this.Address != null &&
this.Address.Equals(other.Address)
);
}
}
public class Address : IEquatable<Address>
{
public int HouseNo { get; set; }
public string Street { get; set; }
public City City { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as Address);
}
public bool Equals(Address other)
{
if (other == null)
return false;
return this.HouseNo.Equals(other.HouseNo) &&
(
object.ReferenceEquals(this.Street, other.Street) ||
this.Street != null &&
this.Street.Equals(other.Street)
) &&
(
object.ReferenceEquals(this.City, other.City) ||
this.City != null &&
this.City.Equals(other.City)
);
}
}
public class City : IEquatable<City>
{
public string Name { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as City);
}
public bool Equals(City other)
{
if (other == null)
return false;
return
object.ReferenceEquals(this.Name, other.Name) ||
this.Name != null &&
this.Name.Equals(other.Name);
}
}
Update: This answer was written several years ago. Since then, I've started to lean away from implementing IEquality<T> for mutable types for such scenarios. There are two notions of equality: identity and equivalence. At a memory representation level, these are popularly distinguished as “reference equality” and “value equality” (see Equality Comparisons). However, the same distinction can also apply at a domain level. Suppose that your Person class has a PersonId property, unique per distinct real-world person. Should two objects with the same PersonId but different Age values be considered equal or different? The answer above assumes that one is after equivalence. However, there are many usages of the IEquality<T> interface, such as collections, that assume that such implementations provide for identity. For example, if you're populating a HashSet<T>, you would typically expect a TryGetValue(T,T) call to return existing elements that share merely the identity of your argument, not necessarily equivalent elements whose contents are completely the same. This notion is enforced by the notes on GetHashCode:
In general, for mutable reference types, you should override GetHashCode() only if:
You can compute the hash code from fields that are not mutable; or
You can ensure that the hash code of a mutable object does not change while the object is contained in a collection that relies on its hash code.

Serialize both objects and compare the resulting strings

You can use extension method, recursion to resolve this problem:
public static bool DeepCompare(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
//Compare two object's class, return false if they are difference
if (obj.GetType() != another.GetType()) return false;
var result = true;
//Get all properties of obj
//And compare each other
foreach (var property in obj.GetType().GetProperties())
{
var objValue = property.GetValue(obj);
var anotherValue = property.GetValue(another);
if (!objValue.Equals(anotherValue)) result = false;
}
return result;
}
public static bool CompareEx(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
if (obj.GetType() != another.GetType()) return false;
//properties: int, double, DateTime, etc, not class
if (!obj.GetType().IsClass) return obj.Equals(another);
var result = true;
foreach (var property in obj.GetType().GetProperties())
{
var objValue = property.GetValue(obj);
var anotherValue = property.GetValue(another);
//Recursion
if (!objValue.DeepCompare(anotherValue)) result = false;
}
return result;
}
or compare by using Json (if object is very complex)
You can use Newtonsoft.Json:
public static bool JsonCompare(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
if (obj.GetType() != another.GetType()) return false;
var objJson = JsonConvert.SerializeObject(obj);
var anotherJson = JsonConvert.SerializeObject(another);
return objJson == anotherJson;
}

If you don't want to implement IEquatable, you can always use Reflection to compare all the properties:
- if they're value type, just compare them
-if they are reference type, call the function recursively to compare its "inner" properties.
I'm not thinking about performace, but about simplicity. It depends, however on the exact design of your objects. It could get complicated depending on your objects shape (for example if there are cyclic dependencies between properties). There are, however, several solutions out there that you can use, like this one:
Compare .NET objects
Another option is to serialize the object as text, for example using JSON.NET, and comparing the serialization result. (JSON.NET can handle Cyclic dependencies between properties).
I don't know if by fastest you mean the fastest way to implement it or a code that runs fast. You should not optimize before knowing if you need to. Premature optimization is the root of all evil

Serialize both objects and compare the resulting strings by #JoelFan
So to do this, create a static class like so and use Extensions to extend ALL objects (so you can pass anytype of object, collection, etc into the method)
using System;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Text;
public static class MySerializer
{
public static string Serialize(this object obj)
{
var serializer = new DataContractJsonSerializer(obj.GetType());
using (var ms = new MemoryStream())
{
serializer.WriteObject(ms, obj);
return Encoding.Default.GetString(ms.ToArray());
}
}
}
Once you reference this static class in any other file, you can do this:
Person p = new Person { Firstname = "Jason", LastName = "Argonauts" };
Person p2 = new Person { Firstname = "Jason", LastName = "Argonaut" };
//assuming you have already created a class person!
string personString = p.Serialize();
string person2String = p2.Serialize();
Now you can simply use .Equals to compare them.
I use this for checking if objects are in collections too. It works really well.

If you have a requirement where you want the class which is immutable. I mean that none of the properties can be modified once it's been created. In that case, C# 9 have a feature which is called a record.
You can easily compare records by values and types is they are equal.
public record Person
{
public string LastName { get; }
public string FirstName { get; }
public Person(string first, string last) => (FirstName, LastName) = (first, last);
}
var person1 = new Person("Bill", "Wagner");
var person2 = new Person("Bill", "Wagner");
Console.WriteLine(person1 == person2); // true

You can now use json.net. Just go on Nuget and install it.
And you can do something like this:
public bool Equals(SamplesItem sampleToCompare)
{
string myself = JsonConvert.SerializeObject(this);
string other = JsonConvert.SerializeObject(sampleToCompare);
return myself == other;
}
You could perhaps make a extension method for object if you wanted to get fancier. Please note this only compares the public properties. And if you wanted to ignore a public property when you do the comparison you could use the [JsonIgnore] attribute.

Serialize both objects, then calculate Hash Code, then compare.

I'll assume you are not referring to literally the same objects
Object1 == Object2
You might be thinking about doing a memory comparison between the two
memcmp(Object1, Object2, sizeof(Object.GetType())
But that's not even real code in c# :). Because all of your data is probably created on the heap, the memory is not contiguous and you can't just compare the equality of two objects in an agnostic manner. You're going to have to compare each value, one at a time, in a custom way.
Consider adding the IEquatable<T> interface to your class, and define a custom Equals method for your type. Then, in that method, manual test each value. Add IEquatable<T> again on enclosed types if you can and repeat the process.
class Foo : IEquatable<Foo>
{
public bool Equals(Foo other)
{
/* check all the values */
return false;
}
}

Based off a few answers already given here I decided to mostly back JoelFan's answer. I love extension methods and these have been working great for me when none of the other solutions would using them to compare my complex classes.
Extension Methods
using System.IO;
using System.Xml.Serialization;
static class ObjectHelpers
{
public static string SerializeObject<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
using (StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
public static bool EqualTo(this object obj, object toCompare)
{
if (obj.SerializeObject() == toCompare.SerializeObject())
return true;
else
return false;
}
public static bool IsBlank<T>(this T obj) where T: new()
{
T blank = new T();
T newObj = ((T)obj);
if (newObj.SerializeObject() == blank.SerializeObject())
return true;
else
return false;
}
}
Usage Examples
if (record.IsBlank())
throw new Exception("Record found is blank.");
if (record.EqualTo(new record()))
throw new Exception("Record found is blank.");

I would say that:
Object1.Equals(Object2)
would be what you're looking for. That's if you're looking to see if the objects are the same, which is what you seem to be asking.
If you want to check to see if all the child objects are the same, run them through a loop with the Equals() method.

I found this below function for comparing objects.
static bool Compare<T>(T Object1, T object2)
{
//Get the type of the object
Type type = typeof(T);
//return false if any of the object is false
if (object.Equals(Object1, default(T)) || object.Equals(object2, default(T)))
return false;
//Loop through each properties inside class and get values for the property from both the objects and compare
foreach (System.Reflection.PropertyInfo property in type.GetProperties())
{
if (property.Name != "ExtensionData")
{
string Object1Value = string.Empty;
string Object2Value = string.Empty;
if (type.GetProperty(property.Name).GetValue(Object1, null) != null)
Object1Value = type.GetProperty(property.Name).GetValue(Object1, null).ToString();
if (type.GetProperty(property.Name).GetValue(object2, null) != null)
Object2Value = type.GetProperty(property.Name).GetValue(object2, null).ToString();
if (Object1Value.Trim() != Object2Value.Trim())
{
return false;
}
}
}
return true;
}
I am using it and it is working fine for me.

Thanks to the example of Jonathan. I expanded it for all cases (arrays, lists, dictionaries, primitive types).
This is a comparison without serialization and does not require the implementation of any interfaces for compared objects.
/// <summary>Returns description of difference or empty value if equal</summary>
public static string Compare(object obj1, object obj2, string path = "")
{
string path1 = string.IsNullOrEmpty(path) ? "" : path + ": ";
if (obj1 == null && obj2 != null)
return path1 + "null != not null";
else if (obj2 == null && obj1 != null)
return path1 + "not null != null";
else if (obj1 == null && obj2 == null)
return null;
if (!obj1.GetType().Equals(obj2.GetType()))
return "different types: " + obj1.GetType() + " and " + obj2.GetType();
Type type = obj1.GetType();
if (path == "")
path = type.Name;
if (type.IsPrimitive || typeof(string).Equals(type))
{
if (!obj1.Equals(obj2))
return path1 + "'" + obj1 + "' != '" + obj2 + "'";
return null;
}
if (type.IsArray)
{
Array first = obj1 as Array;
Array second = obj2 as Array;
if (first.Length != second.Length)
return path1 + "array size differs (" + first.Length + " vs " + second.Length + ")";
var en = first.GetEnumerator();
int i = 0;
while (en.MoveNext())
{
string res = Compare(en.Current, second.GetValue(i), path);
if (res != null)
return res + " (Index " + i + ")";
i++;
}
}
else if (typeof(System.Collections.IEnumerable).IsAssignableFrom(type))
{
System.Collections.IEnumerable first = obj1 as System.Collections.IEnumerable;
System.Collections.IEnumerable second = obj2 as System.Collections.IEnumerable;
var en = first.GetEnumerator();
var en2 = second.GetEnumerator();
int i = 0;
while (en.MoveNext())
{
if (!en2.MoveNext())
return path + ": enumerable size differs";
string res = Compare(en.Current, en2.Current, path);
if (res != null)
return res + " (Index " + i + ")";
i++;
}
}
else
{
foreach (PropertyInfo pi in type.GetProperties(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
try
{
var val = pi.GetValue(obj1);
var tval = pi.GetValue(obj2);
if (path.EndsWith("." + pi.Name))
return null;
var pathNew = (path.Length == 0 ? "" : path + ".") + pi.Name;
string res = Compare(val, tval, pathNew);
if (res != null)
return res;
}
catch (TargetParameterCountException)
{
//index property
}
}
foreach (FieldInfo fi in type.GetFields(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
var val = fi.GetValue(obj1);
var tval = fi.GetValue(obj2);
if (path.EndsWith("." + fi.Name))
return null;
var pathNew = (path.Length == 0 ? "" : path + ".") + fi.Name;
string res = Compare(val, tval, pathNew);
if (res != null)
return res;
}
}
return null;
}
For easy copying of the code created repository

public class GetObjectsComparison
{
public object FirstObject, SecondObject;
public BindingFlags BindingFlagsConditions= BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
}
public struct SetObjectsComparison
{
public FieldInfo SecondObjectFieldInfo;
public dynamic FirstObjectFieldInfoValue, SecondObjectFieldInfoValue;
public bool ErrorFound;
public GetObjectsComparison GetObjectsComparison;
}
private static bool ObjectsComparison(GetObjectsComparison GetObjectsComparison)
{
GetObjectsComparison FunctionGet = GetObjectsComparison;
SetObjectsComparison FunctionSet = new SetObjectsComparison();
if (FunctionSet.ErrorFound==false)
foreach (FieldInfo FirstObjectFieldInfo in FunctionGet.FirstObject.GetType().GetFields(FunctionGet.BindingFlagsConditions))
{
FunctionSet.SecondObjectFieldInfo =
FunctionGet.SecondObject.GetType().GetField(FirstObjectFieldInfo.Name, FunctionGet.BindingFlagsConditions);
FunctionSet.FirstObjectFieldInfoValue = FirstObjectFieldInfo.GetValue(FunctionGet.FirstObject);
FunctionSet.SecondObjectFieldInfoValue = FunctionSet.SecondObjectFieldInfo.GetValue(FunctionGet.SecondObject);
if (FirstObjectFieldInfo.FieldType.IsNested)
{
FunctionSet.GetObjectsComparison =
new GetObjectsComparison()
{
FirstObject = FunctionSet.FirstObjectFieldInfoValue
,
SecondObject = FunctionSet.SecondObjectFieldInfoValue
};
if (!ObjectsComparison(FunctionSet.GetObjectsComparison))
{
FunctionSet.ErrorFound = true;
break;
}
}
else if (FunctionSet.FirstObjectFieldInfoValue != FunctionSet.SecondObjectFieldInfoValue)
{
FunctionSet.ErrorFound = true;
break;
}
}
return !FunctionSet.ErrorFound;
}

Generic Extension Method
public static class GenericExtensions
{
public static bool DeepCompare<T>(this T objA, T objB)
{
if (typeof(T).IsValueType)
return objA.Equals(objB);
if (ReferenceEquals(objA, objB))
return true;
if ((objA == null) || (objB == null))
return false;
if (typeof(T) is IEnumerable)
{
var enumerableA = (IEnumerable<T>) objA;
var enumerableB = (IEnumerable<T>) objB;
if (enumerableA.Count() != enumerableB.Count())
return false;
using (var enumeratorA = enumerableA.GetEnumerator())
using (var enumeratorB = enumerableB.GetEnumerator())
{
while (true)
{
bool moveNextA = enumeratorA.MoveNext();
bool moveNextB = enumeratorB.MoveNext();
if (!moveNextA || !moveNextB)
break;
var currentA = enumeratorA.Current;
var currentB = enumeratorB.Current;
if (!currentA.DeepCompare<T>(currentB))
return false;
}
return true;
}
}
foreach (var property in objA.GetType().GetProperties())
{
var valueA = property.GetValue(objA);
var valueB = property.GetValue(objB);
if (!valueA.DeepCompare(valueB))
return false;
}
return true;
}
}

One way to do this would be to override Equals() on each type involved. For example, your top level object would override Equals() to call the Equals() method of all 5 child objects. Those objects should all override Equals() as well, assuming they are custom objects, and so on until the entire hierarchy could be compared by just performing an equality check on the top level objects.

Use IEquatable<T> Interface which has a method Equals.

To return each property updated:
public IEnumerable<string> GetPropsUpdated(T oldModel, T newModel)
{
var diff = new List<string>();
foreach (var prop in oldModel.GetType().GetProperties())
{
var oldValue = prop.GetValue(oldModel);
var newValue = prop.GetValue(newModel);
if (oldValue == null && newValue == null)
continue;
if (oldValue == null && newValue != null
|| oldValue != null && newValue == null)
{
diff.Add(prop.Name);
continue;
}
var oldPropHashed = oldValue.GetHashCode();
var newPropHashed = newValue.GetHashCode();
if (!oldPropHashed.Equals(newPropHashed))
diff.Add(prop.Name);
}
return diff;
}

Get property value from string using reflection

I am trying implement the Data transformation using Reflection1 example in my code.
The GetSourceValue function has a switch comparing various types, but I want to remove these types and properties and have GetSourceValue get the value of the property using only a single string as the parameter. I want to pass a class and property in the string and resolve the value of the property.
Is this possible?
1 Web Archive version of original blog post

public static object GetPropValue(object src, string propName)
{
return src.GetType().GetProperty(propName).GetValue(src, null);
}
Of course, you will want to add validation and whatnot, but that is the gist of it.

How about something like this:
public static Object GetPropValue(this Object obj, String name) {
foreach (String part in name.Split('.')) {
if (obj == null) { return null; }
Type type = obj.GetType();
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
return obj;
}
public static T GetPropValue<T>(this Object obj, String name) {
Object retval = GetPropValue(obj, name);
if (retval == null) { return default(T); }
// throws InvalidCastException if types are incompatible
return (T) retval;
}
This will allow you to descend into properties using a single string, like this:
DateTime now = DateTime.Now;
int min = GetPropValue<int>(now, "TimeOfDay.Minutes");
int hrs = now.GetPropValue<int>("TimeOfDay.Hours");
You can either use these methods as static methods or extensions.

Add to any Class:
public class Foo
{
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
public string Bar { get; set; }
}
Then, you can use as:
Foo f = new Foo();
// Set
f["Bar"] = "asdf";
// Get
string s = (string)f["Bar"];

What about using the CallByName of the Microsoft.VisualBasic namespace (Microsoft.VisualBasic.dll)? It uses reflection to get properties, fields, and methods of normal objects, COM objects, and even dynamic objects.
using Microsoft.VisualBasic;
using Microsoft.VisualBasic.CompilerServices;
and then
Versioned.CallByName(this, "method/function/prop name", CallType.Get).ToString();

Great answer by jheddings. I would like to improve it by allowing referencing of aggregated arrays or collections of objects, so that propertyName could be property1.property2[X].property3:
public static object GetPropertyValue(object srcobj, string propertyName)
{
if (srcobj == null)
return null;
object obj = srcobj;
// Split property name to parts (propertyName could be hierarchical, like obj.subobj.subobj.property
string[] propertyNameParts = propertyName.Split('.');
foreach (string propertyNamePart in propertyNameParts)
{
if (obj == null) return null;
// propertyNamePart could contain reference to specific
// element (by index) inside a collection
if (!propertyNamePart.Contains("["))
{
PropertyInfo pi = obj.GetType().GetProperty(propertyNamePart);
if (pi == null) return null;
obj = pi.GetValue(obj, null);
}
else
{ // propertyNamePart is areference to specific element
// (by index) inside a collection
// like AggregatedCollection[123]
// get collection name and element index
int indexStart = propertyNamePart.IndexOf("[")+1;
string collectionPropertyName = propertyNamePart.Substring(0, indexStart-1);
int collectionElementIndex = Int32.Parse(propertyNamePart.Substring(indexStart, propertyNamePart.Length-indexStart-1));
// get collection object
PropertyInfo pi = obj.GetType().GetProperty(collectionPropertyName);
if (pi == null) return null;
object unknownCollection = pi.GetValue(obj, null);
// try to process the collection as array
if (unknownCollection.GetType().IsArray)
{
object[] collectionAsArray = unknownCollection as object[];
obj = collectionAsArray[collectionElementIndex];
}
else
{
// try to process the collection as IList
System.Collections.IList collectionAsList = unknownCollection as System.Collections.IList;
if (collectionAsList != null)
{
obj = collectionAsList[collectionElementIndex];
}
else
{
// ??? Unsupported collection type
}
}
}
}
return obj;
}

If I use the code from Ed S. I get
'ReflectionExtensions.GetProperty(Type, string)' is inaccessible due to its protection level
It seems that GetProperty() is not available in Xamarin.Forms. TargetFrameworkProfile is Profile7 in my Portable Class Library (.NET Framework 4.5, Windows 8, ASP.NET Core 1.0, Xamarin.Android, Xamarin.iOS, Xamarin.iOS Classic).
Now I found a working solution:
using System.Linq;
using System.Reflection;
public static object GetPropValue(object source, string propertyName)
{
var property = source.GetType().GetRuntimeProperties().FirstOrDefault(p => string.Equals(p.Name, propertyName, StringComparison.OrdinalIgnoreCase));
return property?.GetValue(source);
}
Source

About the nested properties discussion, you can avoid all the reflection stuff if you use the DataBinder.Eval Method (Object, String) as below:
var value = DataBinder.Eval(DateTime.Now, "TimeOfDay.Hours");
Of course, you'll need to add a reference to the System.Web assembly, but this probably isn't a big deal.

The method to call has changed in .NET Standard (as of 1.6). Also we can use C# 6's null conditional operator.
using System.Reflection;
public static object GetPropValue(object src, string propName)
{
return src.GetType().GetRuntimeProperty(propName)?.GetValue(src);
}

The below method works perfect for me:
class MyClass {
public string prop1 { set; get; }
public object this[string propertyName]
{
get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
}
}
To get the property value:
MyClass t1 = new MyClass();
...
string value = t1["prop1"].ToString();
To set the property value:
t1["prop1"] = value;

public static List<KeyValuePair<string, string>> GetProperties(object item) //where T : class
{
var result = new List<KeyValuePair<string, string>>();
if (item != null)
{
var type = item.GetType();
var properties = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (var pi in properties)
{
var selfValue = type.GetProperty(pi.Name).GetValue(item, null);
if (selfValue != null)
{
result.Add(new KeyValuePair<string, string>(pi.Name, selfValue.ToString()));
}
else
{
result.Add(new KeyValuePair<string, string>(pi.Name, null));
}
}
}
return result;
}
This is a way to get all properties with their values in a List.

Using PropertyInfo of the System.Reflection namespace. Reflection compiles just fine no matter what property we try to access. The error will come up during run-time.
public static object GetObjProperty(object obj, string property)
{
Type t = obj.GetType();
PropertyInfo p = t.GetProperty("Location");
Point location = (Point)p.GetValue(obj, null);
return location;
}
It works fine to get the Location property of an object
Label1.Text = GetObjProperty(button1, "Location").ToString();
We'll get the Location : {X=71,Y=27}
We can also return location.X or location.Y on the same way.

public class YourClass
{
//Add below line in your class
public object this[string propertyName] => GetType().GetProperty(propertyName)?.GetValue(this, null);
public string SampleProperty { get; set; }
}
//And you can get value of any property like this.
var value = YourClass["SampleProperty"];

The following code is a Recursive method for displaying the entire hierarchy of all of the Property Names and Values contained in an object's instance. This method uses a simplified version of AlexD's GetPropertyValue() answer above in this thread. Thanks to this discussion thread, I was able to figure out how to do this!
For example, I use this method to show an explosion or dump of all of the properties in a WebService response by calling the method as follows:
PropertyValues_byRecursion("Response", response, false);
public static object GetPropertyValue(object srcObj, string propertyName)
{
if (srcObj == null)
{
return null;
}
PropertyInfo pi = srcObj.GetType().GetProperty(propertyName.Replace("[]", ""));
if (pi == null)
{
return null;
}
return pi.GetValue(srcObj);
}
public static void PropertyValues_byRecursion(string parentPath, object parentObj, bool showNullValues)
{
/// Processes all of the objects contained in the parent object.
/// If an object has a Property Value, then the value is written to the Console
/// Else if the object is a container, then this method is called recursively
/// using the current path and current object as parameters
// Note: If you do not want to see null values, set showNullValues = false
foreach (PropertyInfo pi in parentObj.GetType().GetTypeInfo().GetProperties())
{
// Build the current object property's namespace path.
// Recursion extends this to be the property's full namespace path.
string currentPath = parentPath + "." + pi.Name;
// Get the selected property's value as an object
object myPropertyValue = GetPropertyValue(parentObj, pi.Name);
if (myPropertyValue == null)
{
// Instance of Property does not exist
if (showNullValues)
{
Console.WriteLine(currentPath + " = null");
// Note: If you are replacing these Console.Write... methods callback methods,
// consider passing DBNull.Value instead of null in any method object parameters.
}
}
else if (myPropertyValue.GetType().IsArray)
{
// myPropertyValue is an object instance of an Array of business objects.
// Initialize an array index variable so we can show NamespacePath[idx] in the results.
int idx = 0;
foreach (object business in (Array)myPropertyValue)
{
if (business == null)
{
// Instance of Property does not exist
// Not sure if this is possible in this context.
if (showNullValues)
{
Console.WriteLine(currentPath + "[" + idx.ToString() + "]" + " = null");
}
}
else if (business.GetType().IsArray)
{
// myPropertyValue[idx] is another Array!
// Let recursion process it.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
else if (business.GetType().IsSealed)
{
// Display the Full Property Path and its Value
Console.WriteLine(currentPath + "[" + idx.ToString() + "] = " + business.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath + "[" + idx.ToString() + "]", business, showNullValues);
}
idx++;
}
}
else if (myPropertyValue.GetType().IsSealed)
{
// myPropertyValue is a simple value
Console.WriteLine(currentPath + " = " + myPropertyValue.ToString());
}
else
{
// Unsealed Type Properties can contain child objects.
// Recurse into my property value object to process its properties and child objects.
PropertyValues_byRecursion(currentPath, myPropertyValue, showNullValues);
}
}
}

public static TValue GetFieldValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetFields(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.FieldType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}
public static TValue GetPropertyValue<TValue>(this object instance, string name)
{
var type = instance.GetType();
var field = type.GetProperties(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance).FirstOrDefault(e => typeof(TValue).IsAssignableFrom(e.PropertyType) && e.Name == name);
return (TValue)field?.GetValue(instance);
}

Dim NewHandle As YourType = CType(Microsoft.VisualBasic.CallByName(ObjectThatContainsYourVariable, "YourVariableName", CallType), YourType)

Here is another way to find a nested property that doesn't require the string to tell you the nesting path. Credit to Ed S. for the single property method.
public static T FindNestedPropertyValue<T, N>(N model, string propName) {
T retVal = default(T);
bool found = false;
PropertyInfo[] properties = typeof(N).GetProperties();
foreach (PropertyInfo property in properties) {
var currentProperty = property.GetValue(model, null);
if (!found) {
try {
retVal = GetPropValue<T>(currentProperty, propName);
found = true;
} catch { }
}
}
if (!found) {
throw new Exception("Unable to find property: " + propName);
}
return retVal;
}
public static T GetPropValue<T>(object srcObject, string propName) {
return (T)srcObject.GetType().GetProperty(propName).GetValue(srcObject, null);
}

You never mention what object you are inspecting, and since you are rejecting ones that reference a given object, I will assume you mean a static one.
using System.Reflection;
public object GetPropValue(string prop)
{
int splitPoint = prop.LastIndexOf('.');
Type type = Assembly.GetEntryAssembly().GetType(prop.Substring(0, splitPoint));
object obj = null;
return type.GetProperty(prop.Substring(splitPoint + 1)).GetValue(obj, null);
}
Note that I marked the object that is being inspected with the local variable obj. null means static, otherwise set it to what you want. Also note that the GetEntryAssembly() is one of a few available methods to get the "running" assembly, you may want to play around with it if you are having a hard time loading the type.

Have a look at the Heleonix.Reflection library. You can get/set/invoke members by paths, or create a getter/setter (lambda compiled into a delegate) which is faster than reflection. For example:
var success = Reflector.Get(DateTime.Now, null, "Date.Year", out int value);
Or create a getter once and cache for reuse (this is more performant but might throw NullReferenceException if an intermediate member is null):
var getter = Reflector.CreateGetter<DateTime, int>("Date.Year", typeof(DateTime));
getter(DateTime.Now);
Or if you want to create a List<Action<object, object>> of different getters, just specify base types for compiled delegates (type conversions will be added into compiled lambdas):
var getter = Reflector.CreateGetter<object, object>("Date.Year", typeof(DateTime));
getter(DateTime.Now);

Although the original question was about how to get the value of the property using only a single string as the parameter, it makes a lot of sense here to use an Expression rather than simply a string to ensure that the caller never uses a hard coded property name. Here is a one line version with usage:
public static class Utils
...
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
=> (TVal)((x.Body as MemberExpression)?.Member as PropertyInfo)!.GetValue(t);
...
var val = Utils.GetPropertyValue(foo, p => p.Bar);
Here is a slightly better version in terms of readability a error handling:
public static TVal GetPropertyValue<T, TVal>(T t, Expression<Func<T, TVal>> x)
{
var m = (x.Body as MemberExpression)?.Member;
var p = m as PropertyInfo;
if (null == p)
throw new ArgumentException($"Unknown property: {typeof(T).Name}.{(m?.Name??"???")}");
return (TVal)p.GetValue(t);
}
In short you pass in a lambda expression reading a property. The body of the lambda - the part on the right of the fat arrow - is a member expression from which you can get the member name and which you can cast to a PropertyInfo, provided the member is actually a Property and not, for instance, a method.
In the short version, the null forgiving operator - the ! in the expression - tells the compiler that the PropertyInfo will not be null. This is a big lie and you will get a NullReferenceException at runtime. The longer version gives you the name of the property if it manages to get it.
PS: Thanks to Oleg G. for the initial version of this code :)

shorter way ....
var a = new Test { Id = 1 , Name = "A" , date = DateTime.Now};
var b = new Test { Id = 1 , Name = "AXXX", date = DateTime.Now };
var compare = string.Join("",a.GetType().GetProperties().Select(x => x.GetValue(a)).ToArray())==
string.Join("",b.GetType().GetProperties().Select(x => x.GetValue(b)).ToArray());

jheddings and AlexD both wrote excellent answers on how to resolve property strings. I'd like to throw mine in the mix, since I wrote a dedicated library exactly for that purpose.
Pather.CSharp's main class is Resolver. Per default it can resolve properties, array and dictionary entries.
So, for example, if you have an object like this
var o = new { Property1 = new { Property2 = "value" } };
and want to get Property2, you can do it like this:
IResolver resolver = new Resolver();
var path = "Property1.Property2";
object result = r.Resolve(o, path);
//=> "value"
This is the most basic example of the paths it can resolve. If you want to see what else it can, or how you can extend it, just head to its Github page.

Here's what I got based on other answers. A little overkill on getting so specific with the error handling.
public static T GetPropertyValue<T>(object sourceInstance, string targetPropertyName, bool throwExceptionIfNotExists = false)
{
string errorMsg = null;
try
{
if (sourceInstance == null || string.IsNullOrWhiteSpace(targetPropertyName))
{
errorMsg = $"Source object is null or property name is null or whitespace. '{targetPropertyName}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
Type returnType = typeof(T);
Type sourceType = sourceInstance.GetType();
PropertyInfo propertyInfo = sourceType.GetProperty(targetPropertyName, returnType);
if (propertyInfo == null)
{
errorMsg = $"Property name '{targetPropertyName}' of type '{returnType}' not found for source object of type '{sourceType}'";
Log.Warn(errorMsg);
if (throwExceptionIfNotExists)
throw new ArgumentException(errorMsg);
else
return default(T);
}
return (T)propertyInfo.GetValue(sourceInstance, null);
}
catch(Exception ex)
{
errorMsg = $"Problem getting property name '{targetPropertyName}' from source instance.";
Log.Error(errorMsg, ex);
if (throwExceptionIfNotExists)
throw;
}
return default(T);
}

Here is my solution. It works also with COM objects and allows to access collection/array items from COM objects.
public static object GetPropValue(this object obj, string name)
{
foreach (string part in name.Split('.'))
{
if (obj == null) { return null; }
Type type = obj.GetType();
if (type.Name == "__ComObject")
{
if (part.Contains('['))
{
string partWithoundIndex = part;
int index = ParseIndexFromPropertyName(ref partWithoundIndex);
obj = Versioned.CallByName(obj, partWithoundIndex, CallType.Get, index);
}
else
{
obj = Versioned.CallByName(obj, part, CallType.Get);
}
}
else
{
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
}
return obj;
}
private static int ParseIndexFromPropertyName(ref string name)
{
int index = -1;
int s = name.IndexOf('[') + 1;
int e = name.IndexOf(']');
if (e < s)
{
throw new ArgumentException();
}
string tmp = name.Substring(s, e - s);
index = Convert.ToInt32(tmp);
name = name.Substring(0, s - 1);
return index;
}

Whenever you want to loop over all properties in on an object and then use each value of the property must use this piece of code:
foreach (var property in request.GetType().GetProperties())
{
var valueOfProperty = property.GetValue(properties, null);
}