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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);
}

.Net accessing instantiated class members by string variable [duplicate]

I have an instance of the Account class. Each account object has an owner, reference, etc.
One way I can access an accounts properties is through accessors like
account.Reference;
but I would like to be able to access it using dynamic string selectors like:
account["PropertyName"];
just like in JavaScript. So I would have account["Reference"] which would return the value, but I also would like to be able to assign a new value after that like:
account["Reference"] = "124ds4EE2s";
I've noticed I can use
DataBinder.Eval(account,"Reference")
to get a property based on a string, but using this I can't assign a value to the property.
Any idea on how I could do that?

First of all, you should avoid using this; C# is a strongly-typed language, so take advantage of the type safety and performance advantages that accompany that aspect.
If you have a legitimate reason to get and set the value of a property dynamically (in other words, when the type and/or property name is not able to be defined in the code), then you'll have to use reflection.
The most inline-looking way would be this:
object value = typeof(YourType).GetProperty("PropertyName").GetValue(yourInstance);
...
typeof(YourType).GetProperty("PropertyName").SetValue(yourInstance, "value");
However, you can cache the PropertyInfo object to make it more readable:
System.Reflection.PropertyInfo prop = typeof(YourType).GetProperty("PropertyName");
object value = prop.GetValue(yourInstance);
...
prop.SetValue(yourInstance, "value");

You could try combining the indexer with reflection...
public object this[string propertyName]
{
get
{
PropertyInfo property = GetType().GetProperty(propertyName);
return property.GetValue(this, null);
}
set
{
PropertyInfo property = GetType().GetProperty(propertyName);
property.SetValue(this,value, null);
}
}

If they are your own objects you could provide an indexer to access the fields. I don't really recommend this but it would allow what you want.
public object this[string propertyName]
{
get
{
if(propertyName == "Reference")
return this.Reference;
else
return null;
}
set
{
if(propertyName == "Reference")
this.Reference = value;
else
// do error case here
}
}
Note that you lose type safety when doing this.

I used the reflection method from Richard, but elaborated the set method to handle other types being used such as strings and nulls.
public object this[string propertyName]
{
get
{
PropertyInfo property = GetType().GetProperty(propertyName);
return property.GetValue(this, null);
}
set
{
PropertyInfo property = GetType().GetProperty(propertyName);
Type propType = property.PropertyType;
if (value == null)
{
if (propType.IsValueType && Nullable.GetUnderlyingType(propType) == null)
{
throw new InvalidCastException();
}
else
{
property.SetValue(this, null, null);
}
}
else if (value.GetType() == propType)
{
property.SetValue(this, value, null);
}
else
{
TypeConverter typeConverter = TypeDescriptor.GetConverter(propType);
object propValue = typeConverter.ConvertFromString(value.ToString());
property.SetValue(this, propValue, null);
}
}
}
The SetValue() function will throw an error if the conversion doesn't work.

If you are using .Net 4 you can use the dynamic keyword now.
dynamic foo = account;
foo.Reference = "124ds4EE2s";

I agree with the previous posters that you probably do need to be using the properties. Reflection is very slow compared to direct property access.
On the other hand, if you need to maintain a list of user-defined properties, then you can't use C# properties. You need to pretend you are a Dictionary, or you need to expose a property that behaves like a Dictionary. Here is an example of how you could make the Account class support user-defined properties:
public class Account
{
Dictionary<string, object> properties;
public object this[string propertyName]
{
get
{
if (properties.ContainsKey[propertyName])
return properties[propertyName];
else
return null;
}
set
{
properties[propertyName] = value;
}
}
}

I personally prefer to work with extension methods so here is my code :
public static class ReflectionExtensions
{
public static void SetPropertyValue(this object Target,
string PropertyName,
object NewValue)
{
if (Target == null) return; //or throw exception
System.Reflection.PropertyInfo prop = Target.GetType().GetProperty(PropertyName);
if (prop == null) return; //or throw exception
object value = prop.GetValue(Target, null);
prop.SetValue(Target, NewValue, null);
}
}

You need to use Reflection:
PropertyInfo property = typeof(Account).GetProperty("Reference");
property.SetValue(myAccount, "...", null);
Note that this will be very slow.

Use reflection and expression bodies
public dynamic this[string memberName]
{
get => GetType().GetProperty(memberName).GetValue(this, null);
set => GetType().GetProperty(memberName).SetValue(this,value, null);
}

how to access the list in an object using reflection by string name
public List Table1 { get; set; } = new List();

Here is a simple example, I hope it helps
static void Main(string[] args)
{
Operators op = new Operators()
{
ID = 1,
Name = "Edward",
email = "e.lorenz#mail.com",
Pass = "123456",
Auth1 = "EDF3242523#FFSDGDF"
};
var typei = op.GetType();
var ss = typei.GetProperties().Where(m => m.GetCustomAttributes<Password>().Count() > 0);
foreach (var item in ss)
{
var text = typei.GetProperty(item.Name).GetValue(op).ToString();
typei.GetProperty(item.Name).SetValue(op, Encrypt(text));
}
Console.WriteLine(op.Pass);
Console.WriteLine(op.Auth1);
Console.ReadKey();
}

Reflection Property.SetValue(

I have the following class to create objects from a delimited line:
public class Mapper<T>
{
public T Map(string line, char delimiter)
{
if(String.IsNullOrEmpty(line))
throw new ArgumentNullException(nameof(line));
if (Char.IsWhiteSpace(delimiter))
throw new ArgumentException(nameof(delimiter));
var splitString = line.Split(delimiter);
var properties = typeof(T).GetProperties();
if(properties.Count() != splitString.Count())
throw new InvalidOperationException($"Row has {splitString.Count()} columns but object has {properties.Count()}.");
var obj = Activator.CreateInstance<T>();
for (var i = 0; i < splitString.Count(); i++)
{
var prop = properties[i];
var propType = prop.PropertyType;
var valType = Convert.ChangeType(splitString[i], propType);
prop.SetValue(obj, valType);
}
return (T)obj;
}
}
If I call the map method with a delimited string it will populate all of the properties on the object with the delimited values from the line.
However when I call this from the following:
public class CsvStreamReader<T>
{
private readonly Mapper<T> _mapper;
public CsvStreamReader(Mapper<T> mapper)
{
_mapper = mapper;
}
public IEnumerable<T> ReadCsvFile(string filePath, bool hasHeader)
{
if(hasHeader)
return File.ReadAllLines(filePath)
.Skip(1)
.Select(x => _mapper.Map(x, ','));
return File.ReadAllLines(filePath)
.Select(x => _mapper.Map(x, ','));
}
}
It will return a list of T but all of the properties will be null and won't have been set.
Update: Just realised my class wasn't a class but was actually a struct.

In order to make your Mapper<T> work when T is a value type, you need to set its properties while boxed as an object. Create your obj as an object using the the non-generic Activator.CreateInstance(typeof(T)), set its properties using reflection, then finally cast the it to the required type when returning it:
public class Mapper<T>
{
readonly List<PropertyInfo> properties = typeof(T).GetProperties().OrderBy(p => p.Name).ToList();
public T Map(string line, char delimiter)
{
if (String.IsNullOrEmpty(line))
throw new ArgumentNullException("line");
if (Char.IsWhiteSpace(delimiter))
throw new ArgumentException("delimiter");
var splitString = line.Split(delimiter);
if (properties.Count() != splitString.Count())
throw new InvalidOperationException(string.Format("Row has {0} columns but object has {1}", splitString.Count(), properties.Count()));
// Create as a reference (boxed if a value type).
object obj = Activator.CreateInstance(typeof(T));
// Set the property values on the object reference.
for (var i = 0; i < splitString.Count(); i++)
{
var prop = properties[i];
var propType = prop.PropertyType;
var valType = Convert.ChangeType(splitString[i], propType);
prop.SetValue(obj, valType);
}
// Cast to the return type unboxing if required.
return (T)obj;
}
}
Sample fiddle.
Note that your code should not depend on the order of properties returned by Type.GetProperties(). From the docs:
The GetProperties method does not return properties in a particular
order, such as alphabetical or declaration order. Your code must not
depend on the order in which properties are returned, because that
order varies.
Thus I modified your code to order by name. You might choose to select another strategy such as using data member order for data contract types.
Finally, you might want to reconsider your design of using mutable structs, see Why are mutable structs “evil”? for some reasons why. To restrict your Mapper<T> to work only for reference types, you can add the following where constraint:
public class Mapper<T> where T : class
{
}

how can I get properties of a model with for loop [duplicate]

From the world of PHP I have decided to give C# a go. I've had a search but can't seem to find the answer of how to do the equivalent to this.
$object = new Object();
$vars = get_class_vars(get_class($object));
foreach($vars as $var)
{
doSomething($object->$var);
}
I basically have a List of an object. The object could be one of three different types and will have a set of public properties. I want to be able to get a list of the properties for the object, loop over them and then write them out to a file.
I'm thinking this has something to do with c# reflection but it's all new to me.
Any help would be greatly appreciated.

This should do it:
Type myType = myObject.GetType();
IList<PropertyInfo> props = new List<PropertyInfo>(myType.GetProperties());
foreach (PropertyInfo prop in props)
{
object propValue = prop.GetValue(myObject, null);
// Do something with propValue
}

void Test(){
var obj = new{a="aaa", b="bbb"};
var val_a = obj.GetValObjDy("a"); //="aaa"
var val_b = obj.GetValObjDy("b"); //="bbb"
}
//create in a static class
static public object GetValObjDy(this object obj, string propertyName)
{
return obj.GetType().GetProperty(propertyName).GetValue(obj, null);
}

Yes, Reflection would be the way to go. First, you would get the Type that represents the type (at runtime) of the instance in the list. You can do this by calling the GetType method on Object. Because it is on the Object class, it's callable by every object in .NET, as all types derive from Object (well, technically, not everything, but that's not important here).
Once you have the Type instance, you can call the GetProperties method to get the PropertyInfo instances which represent the run-time informationa about the properties on the Type.
Note, you can use the overloads of GetProperties to help classify which properties you retrieve.
From there, you would just write the information out to a file.
Your code above, translated, would be:
// The instance, it can be of any type.
object o = <some object>;
// Get the type.
Type type = o.GetType();
// Get all public instance properties.
// Use the override if you want to classify
// which properties to return.
foreach (PropertyInfo info in type.GetProperties())
{
// Do something with the property info.
DoSomething(info);
}
Note that if you want method information or field information, you would have to call the one of the overloads of the GetMethods or GetFields methods respectively.
Also note, it's one thing to list out the members to a file, but you shouldn't use this information to drive logic based on property sets.
Assuming you have control over the implementations of the types, you should derive from a common base class or implement a common interface and make the calls on those (you can use the as or is operator to help determine which base class/interface you are working with at runtime).
However, if you don't control these type definitions and have to drive logic based on pattern matching, then that's fine.

well, in C# it's similar.
Here's one of the simplest examples (only for public properties):
var someObject = new { .../*properties*/... };
var propertyInfos = someObject.GetType().GetProperties();
foreach (PropertyInfo pInfo in propertyInfos)
{
string propertyName = pInfo.Name; //gets the name of the property
doSomething(pInfo.GetValue(someObject,null));
}

One line solution using Linq...
var obj = new {Property1 = 1, Property2 = 2};
var property1 = obj.GetType().GetProperties().First(o => o.Name == "Property1").GetValue(obj , null);

To get specific property value from property name
public class Bike{
public string Name {get;set;}
}
Bike b = new Bike {Name = "MyBike"};
to access property value of Name from string name of property
public object GetPropertyValue(string propertyName)
{
//returns value of property Name
return this.GetType().GetProperty(propertyName).GetValue(this, null);
}

You can use GetType - GetProperties - Linq Foreach:
obj.GetType().GetProperties().ToList().ForEach(p =>{
//p is each PropertyInfo
DoSomething(p);
});

Here's something I use to transform an IEnumerable<T> into a DataTable that contains columns representing T's properties, with one row for each item in the IEnumerable:
public static DataTable ToDataTable<T>(IEnumerable<T> items)
{
var table = CreateDataTableForPropertiesOfType<T>();
PropertyInfo[] piT = typeof(T).GetProperties();
foreach (var item in items)
{
var dr = table.NewRow();
for (int property = 0; property < table.Columns.Count; property++)
{
if (piT[property].CanRead)
{
var value = piT[property].GetValue(item, null);
if (piT[property].PropertyType.IsGenericType)
{
if (value == null)
{
dr[property] = DBNull.Value;
}
else
{
dr[property] = piT[property].GetValue(item, null);
}
}
else
{
dr[property] = piT[property].GetValue(item, null);
}
}
}
table.Rows.Add(dr);
}
return table;
}
public static DataTable CreateDataTableForPropertiesOfType<T>()
{
DataTable dt = new DataTable();
PropertyInfo[] piT = typeof(T).GetProperties();
foreach (PropertyInfo pi in piT)
{
Type propertyType = null;
if (pi.PropertyType.IsGenericType)
{
propertyType = pi.PropertyType.GetGenericArguments()[0];
}
else
{
propertyType = pi.PropertyType;
}
DataColumn dc = new DataColumn(pi.Name, propertyType);
if (pi.CanRead)
{
dt.Columns.Add(dc);
}
}
return dt;
}
This is "somewhat" overcomplicated, but it's actually quite good for seeing what the outcome is, as you can give it a List<T> of, for example:
public class Car
{
string Make { get; set; }
int YearOfManufacture {get; set; }
}
And you'll be returned a DataTable with the structure:
Make (string)
YearOfManufacture (int)
With one row per item in your List<Car>

This example trims all the string properties of an object.
public static void TrimModelProperties(Type type, object obj)
{
var propertyInfoArray = type.GetProperties(
BindingFlags.Public |
BindingFlags.Instance);
foreach (var propertyInfo in propertyInfoArray)
{
var propValue = propertyInfo.GetValue(obj, null);
if (propValue == null)
continue;
if (propValue.GetType().Name == "String")
propertyInfo.SetValue(
obj,
((string)propValue).Trim(),
null);
}
}

I haven't found this to work on, say Application objects. I have however had success with
var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
string rval = serializer.Serialize(myAppObj);

You can try this:
string[] arr = ((IEnumerable)obj).Cast<object>()
.Select(x => x.ToString())
.ToArray();
Once every array implements IEnumerable interface

public Dictionary<string, string> ToDictionary(object obj)
{
Dictionary<string, string> dictionary = new Dictionary<string, string>();
Type objectType = obj.GetType();
IList<PropertyInfo> props = new List<PropertyInfo>(objectType.GetProperties());
foreach (PropertyInfo prop in props)
{
object propValue = prop.GetValue(obj, null);
dictionary.Add(prop.Name, propValue.ToString());
}
return dictionary;
}

/// get set value field in object to object new (two object field like )
public static void SetValueObjectToObject (object sourceObj , object resultObj)
{
IList<PropertyInfo> props = new List<PropertyInfo>(sourceObj.GetType().GetProperties());
foreach (PropertyInfo prop in props)
{
try
{
//get value in sourceObj
object propValue = prop.GetValue(sourceObj, null);
//set value in resultObj
PropertyInfo propResult = resultObj.GetType().GetProperty(prop.Name, BindingFlags.Public | BindingFlags.Instance);
if (propResult != null && propResult.CanWrite)
{
propResult.SetValue(resultObj, propValue, null);
}
}
catch (Exception ex)
{
// do something with Ex
}
}
}

process items in Generic list/collections with Reflection

I have a generic class that I am using Reflection to pull out the properties of the type of the generic and looking for an attribute. I am recursing into each property to do the same for each of their properties. My issue is when I come to some sort of collection property (property that is a collection) or ICollection property. I will not be able to cast the value returned from GetValue into a specific type (tried to cast into IEnumerable but does not work for generic IEnumerables).
Here is some code to help understand a little more:
public class NotificationMessageProcessor<T> : INotificationProcessor<T>
{
IList<string> availableTags = new List<string>();
public string ReplaceNotificationTags<T>(string message, T instance)
{
LoadTagValues(instance);
return ReplaceTags(message);
}
private string ReplaceTags(string message)
{
foreach (KeyValuePair<string, string> tagVal in tagValues)
{
message = message.Replace(string.Format("<{0}>", tagVal.Key), tagVal.Value);
}
return message;
}
private void LoadTagValues(object val)
{
Type elementType = val.GetType();
PropertyInfo[] typeProperties = elementType.GetProperties();
foreach (PropertyInfo prop in typeProperties)
{
NotificationTag[] tags = (NotificationTag[])prop.GetCustomAttributes(typeof(NotificationTag), false);
if (tags != null && tags.Length > 0)
{
string tagName = tags[0].TagName;
object propValue = prop.GetValue(val, null);
string propTypeString = prop.PropertyType.FullName;
tagName = prop.ReflectedType.Name + "." + tagName;
if (propValue != null)
{
tagValues.Add(tagName, propValue.ToString());
}
if (propValue != null)
{
if (!prop.PropertyType.IsPrimitive)
{
LoadTagValues(propValue);
}
}
}
else
{
if (!prop.PropertyType.IsPrimitive)
{
object propValue = null;
if (prop.GetGetMethod().GetParameters().Count() == 0)
{
propValue = prop.GetValue(val, null);
}
else
{
//have a collection...need to process but do not know how many in collection....
propValue = prop.GetValue(val, new object[] { 0 });
}
if (propValue != null)
{
LoadTagValues(propValue);
}
}
}
}
}
NotificationMessageProcessor<User> userProcessor = new NotificationMessageProcessor();
userProcessor.ReplaceNotificationTags<User>(someMessage, instanceOfUser);
The User object has the proper attributes

From what I understand, non-generic IEnumerable will do since you don't need the type information anyway.

You could try casting the collection type of the property to the actual type of collection?
are you doing something like the following:
List<OfObject> myCollection = new List<OfObject>;
myCollection = (List<OfObject>)objPropertyInfo.GetValue(List<ObjectHere>, Nothing);
Hope this helps

I am doing the cast to IEnumerable, I was trying to cast the wrong object when I was having issues.

Last Answer (Anton Gogolev) is one of the best; for example:
I had this generic function:
var fieldFetchedData = fieldQueryHandler.GetType().GetMethod("GetFilter").MakeGenericMethod(selectedParameter.ParameterType).Invoke(fieldQueryHandler,fieldParameters.ToArray());
which itself also returned a generic list (List<[Unknown Model Type]>...)
I looked everywhere to get a single result from it, but I had to cast it any way before doing that, and there was no way to define user or any other model class (which I don't know which one it should be) even through generics. Once I saw it, I said to myself, I tried many ways, let also give this a try, and so I did it like this:
IEnumerator enumeratorFetchedData = ((IEnumerable) fieldFetchedData).GetEnumerator();
object obj = enumeratorFetchedData.MoveNext()? enumeratorFetchedData.Current:null;
and it worked as it should!!