I have a class which i want to retrieve a property from it dynamically
here is a sample from the class
namespace TEST
{
public class Data
{
public string Username { get; set; }
public string Password { get; set; }
}
}
i am trying to use GetProperty but it always return null
static object PropertyGet(object p, string propName)
{
Type t = p.GetType();
PropertyInfo info = t.GetProperty(propName);
if (info == null)
return null;
return info.GetValue(propName);
}
like this
var data = new Data();
var x = PropertyGet(data, "Username");
Console.Write(x?? "NULL");
This line is wrong, and should be throwing an exception for you:
return info.GetValue(propName);
You need to pass in the object from which to extract the property, i.e.
return info.GetValue(p);
Also note that currently data.Username is null. You want something like:
var data = new Data { Username = "Fred" };
I've validated that with these two changes, it works.
This works:
public class Data
{
public string Username { get; set; }
public string Password { get; set; }
}
public class Program
{
static object PropertyGet(object p, string propName)
{
Type t = p.GetType();
PropertyInfo info = t.GetProperty(propName);
if (info == null)
{
return null;
}
else
{
return info.GetValue(p, null);
}
}
static void Main(string[] args)
{
var data = new Data() { Username = "Fred" };
var x = PropertyGet(data, "Username");
Console.Write(x ?? "NULL");
}
}
Related
I'd like an extension method to create an object based on another but keep only the primitive properties. This object will be dumped into a log file in JSON format for logging.
Based on the classes shown below, in this sample, the created object should keep only these properties :
public string FirstName { get; set; }
public string LastName { get; set; }
public int Age { get; set; }
I am using .NET Framework 4.7
How can I do this?
// To use like this
var order = new Order();
var forLog = order.RemovePrimitives();
// Sample of classes
public class Order
{
public string FirstName { get; set; }
public string LastName { get; set; }
public int Age { get; set; }
public List<Item> Items { get; set; }
public Address Address { get; set; }
}
public class Item{}
public class Address{}
public static class Extensions
{
public static string RemovePrimitives(this object obj)
{
// I need to create an anonymous, named 'TheNewObjectHere' object but only with primitives
// I will dump the object to push to a log file. I need only primitives
return JsonConvert.SerializeObject(TheNewObjectHere, Formatting.Indented);
}
}
Thanks
try this
public static class Extensions
{
public static string RemovePrimitives(this object obj)
{
var jsonObj = JObject.FromObject(obj);
var propToRemove = jsonObj.Properties().Where(i => !i.Value.GetType().ToString()
.Contains("JValue")).ToList();
foreach (var prop in propToRemove) prop.Remove();
return jsonObj.ToString();
}
}
You can use reflection to get primitive properties and then use JObject to build a JSON object dynamically.
public static readonly Type[] AdditionalPrimities = new[] { typeof(decimal), typeof(string) };
public static string RemovePrimitives<T>(this T obj)
{
var jObj = new JObject();
var props = GetPrimitiveProperties(obj);
foreach (var item in props)
{
var value = item.GetValue(obj);
if (value != null)
{
jObj.Add(item.Name, new JValue(value));
}
}
return jObj.ToString(Newtonsoft.Json.Formatting.Indented);
}
public static PropertyInfo[] GetPrimitiveProperties<T>()
{
var properties = typeof(T)
.GetProperties(BindingFlags.Instance | BindingFlags.Public)
.Where(r => r.PropertyType.IsPrimitive || (r.PropertyType.IsGenericType && Nullable.GetUnderlyingType(r.PropertyType) != null) || AdditionalPrimities.Contains(r.PropertyType))
.Select(r => r)
.ToArray();
return properties;
}
public static void Main()
{
var order = new Order { FirstName = "abc", LastName = "cde", Address = new Address(), Age2 = 3, Age = 1 };
var final = order.RemovePrimitives();
Console.WriteLine(final);
}
Fiddle
Let's say we have a class Root that has BasicDetails class property and then basicDetails has two properties. A string "Name" and a dynamic object called "CustomAttributes".
I want to get the value in the following manner:
var root = new Root();
root.BasicDetails.Name = "Samurai";
root.BasicDetails.CustomAttributes.phone = "12345";
string res1 = GetDeepPropertyValue(root, "BasicDetails.CustomAttributes.Phone").ToString();
string res2 = GetDeepPropertyValue(root, "BasicDetails.Name").ToString();
The following is the code I have tried (based on another answer on SO):
public static object GetDeepPropertyValue(object src, string propName)
{
if (propName.Contains('.'))
{
string[] Split = propName.Split('.');
string RemainingProperty = propName.Substring(propName.IndexOf('.') + 1);
return GetDeepPropertyValue(src.GetType().GetProperty(Split[0]).GetValue(src, null), RemainingProperty);
}
else
return src.GetType().GetProperty(propName).GetValue(src, null);
}
The following are the classes:
public class Root
{
public Root()
{
BasicDetails = new BasicDetails();
}
public BasicDetails BasicDetails { get;set;}
}
public class BasicDetails
{
public BasicDetails()
{
CustomAttributes = new ExpandoObject();
}
public string Name { get; set; }
public dynamic CustomAttributes { get; set; }
}
The function that I have tried is throwing null reference error. Unfortunately I do not understand reflection too well so at the moment I am monkey patching. If someone could please explain c#how this can be done it would be great. Thank you in advance.
Following method gets values from nested properties:
public static object GetPropertyValue(object src, string propName)
{
if (src == null) throw new ArgumentException("Value cannot be null.", "src");
if (propName == null) throw new ArgumentException("Value cannot be null.", "propName");
if (propName.Contains("."))//complex type nested
{
var temp = propName.Split(new char[] { '.' }, 2);
return GetPropertyValue(GetPropertyValue(src, temp[0]), temp[1]);
}
else
{
if (src is ExpandoObject)
{
var expando = src as IDictionary<string, object>;
if (expando != null)
{
object obj;
expando.TryGetValue(propName, out obj);
return obj;
}
return null;
}
else
{
var prop = src.GetType().GetProperty(propName);
return prop != null ? prop.GetValue(src, null) : null;
}
}
}
Usage:
string res1 = GetPropertyValue(root, "BasicDetails.CustomAttributes.phone") as string;
string res2 = GetPropertyValue(root, "BasicDetails.Name") as string;
I have a list where TestClass is a class with some predefined properties. So when i get data and bind my list with data i need to ignore some properties of TestClass by comparing it with a list. How can i achieve that?
Below is my code
public class TestClass
{
public int id{get;set;}
public string fname{get;set;}
public string lname{get;set;}
public string job {get;set;}
public string role{get;set;}
public string address{get;set;}
}
List<TestClass> ulist = null;
ulist = ToList<TestClass>(usersdataset.tables[0]); //fill my list with the data code is given below
so after getting the data into the list i need to remove some properties by comparing it with list of properties which should be returned.for example if my filteredlist should only show id,fname,role then i need to remove the extra properties from my ulist. so after the filter ulist should only contain id,fname and role
ToList Method
public static List<T> ToList<T>(DataTable dataTable) where T : new()
{
var dataList = new List<T>();
//Define what attributes to be read from the class
const BindingFlags flags = BindingFlags.Public | BindingFlags.Instance;
//Read Attribute Names and Types
var objFieldNames = typeof(T).GetProperties(flags).Cast<PropertyInfo>().
Select(item => new
{
Name = item.Name,
Type = Nullable.GetUnderlyingType(item.PropertyType) ?? item.PropertyType
}).ToList();
//Read Datatable column names and types
var dtlFieldNames = dataTable.Columns.Cast<DataColumn>().
Select(item => new {
Name = item.ColumnName,
Type = item.DataType
}).ToList();
foreach (DataRow dataRow in dataTable.AsEnumerable().ToList())
{
var classObj = new T();
foreach (var dtField in dtlFieldNames)
{
PropertyInfo propertyInfos = classObj.GetType().GetProperty(dtField.Name);
var field = objFieldNames.Find(x => x.Name == dtField.Name);
//var field = filteredColumns.Find(x => x.PropertyName == dtField.Name);
if (field != null)
{
if (dataRow[dtField.Name] != DBNull.Value)
propertyInfos.SetValue(classObj, dataRow[dtField.Name], null);
}
}
dataList.Add(classObj);
}
return dataList;
}
Use the overvride function Equals:
This sample compare only the id property
public class TestClass
{
public int id { get; set; }
public string fname { get; set; }
public string lname { get; set; }
public string job { get; set; }
public string role { get; set; }
public string address { get; set; }
public override bool Equals(object obj)
{
if (obj.GetType().Name != this.GetType().Name)
{
return false;
}
TestClass testclassObject = (TestClass)obj;
if (testclassObject.id != this.id)
{
return false;
}
return true;
}
I have the following class Franchise:
public class Franchise
{
public string FolderName { get; set; }
public string InstallerExeName { get; set; }
}
I have a method that checks specific property value for uniqness among all franchises in the db.
public bool ValidateFolderName(string folderName)
{
var allFranchises = _franchiseService.GetAll();
var result = allFranchises.Any(f => f.FolderName == folderName);
return result;
}
The problem is I have to check another property for uniqness:
public bool ValidateInstallerExeName(string installerExeName)
{
var allFranchises = _franchiseService.GetAll();
var result = allFranchises.Any(f => f.InstallerExeName == installerExeName);
return result;
}
I want to avoid code duplication by making a generic method. Something like:
public bool ValidateProperty(string propertyName)
{
var allFranchises = _franchiseService.GetAll();
// Not sure how to write this line
var result = allFranchises.Any(f => f.[propertyName] == propertyName);
return result;
}
The problem is I am not sure how to re-write this line of code so that it can get the property name and check its value by the provided parameter:
var result = allFranchises.Any(f => f.[propertyName] == propertyName);
I know I can do something like this with reflection:
franchise.GetType().GetProperty(propertyName).GetValue(franchise, null);
but I am not sure how can I make this to fit my case. Any help with working example will be greatly appreciated. Thanks!
Here is a full working example using reflection:
class Program
{
private static List<Franchise> allFranchises;
static void Main(string[] args)
{
allFranchises = new List<Franchise>
{
new Franchise() { FolderName=#"c:\1", InstallerExeName="1.exe" },
new Franchise() { FolderName=#"c:\2", InstallerExeName="2.exe" },
new Franchise() { FolderName=#"c:\3", InstallerExeName="3.exe" },
new Franchise() { FolderName=#"c:\4", InstallerExeName="4.exe" },
new Franchise() { FolderName=#"c:\5", InstallerExeName="5.exe" },
};
Console.WriteLine(ValidateProperty("FolderName", #"c:\2", allFranchises));
Console.WriteLine(ValidateProperty("InstallerExeName", "5.exe", allFranchises));
Console.WriteLine(ValidateProperty("FolderName", #"c:\7", allFranchises));
Console.WriteLine(ValidateProperty("InstallerExeName", "12.exe", allFranchises));
}
public static bool ValidateProperty(string propertyName, object propertyValue, IEnumerable<Franchise> validateAgainst)
{
PropertyInfo propertyInfo = typeof(Franchise).GetProperty(propertyName);
return validateAgainst.Any(f => propertyInfo.GetValue(f, null) == propertyValue);
}
}
public class Franchise
{
public string FolderName { get; set; }
public string InstallerExeName { get; set; }
}
It will print out:
True
True
False
False
as expected.
public bool ValidateProperty<TType, TPropertyType>(Func<TType, TPropertyType> propertySelector, TPropertyType propertyValue)
{
return _franchiseService.GetAll().Any(f => propertySelector(f) == propertyValue);
}
You can call it like this:
if( ValidateProperty(x => x.FirstName, "Joe") )
This does not use reflection and you have intellisense for your propertyname as well.
You may use an extension method:
public static bool ValidateProperty(
this IEnumerable<Franchise> franchises,
string property,
object value)
{
var prop = typeof(Franchise).GetProperty(property);
if (prop == null)
throw new ArgumentException("Property does not exist");
return franchises.Any(f =>
prop.GetValue(f) == value);
}
Use it like this:
var r = _franchiseService.GetAll().ValidateProperty("FolderName", "myfolder1");
You can build the function you want using System.Linq.Expressions
public class Franchise
{
public string FolderName { get; set; }
public string InstallerExeName { get; set; }
bool ValidateProperty(string propertyName) {
var allFranchises = new List<Franchise>();
var parameter = Expression.Parameter(typeof(Franchise));
var property = Expression.Property(parameter, propertyName);
var thisExpression = Expression.Constant(this, typeof(Franchise));
var value = Expression.Property(thisExpression, propertyName);
var notThis = Expression.ReferenceNotEqual(thisExpression, property);
var equal = Expression.Equal(value, property);
var lambda = Expression.Lambda<Func<Franchise, bool>>(Expression.And(notThis, equal));
// lamda is now the equivalent of:
// x => !object.ReferenceEquals(this, x) && object.Equals(x.Property, this.Property)
return allFranchises.Any(lambda.Compile());
}
}
If allFranchises is of type IQueryable you use allFranchises.Any(lambda)
You could also caches the expression for later use if you are worried about performance.
}
I am not sure if this is possible but I want to iterate through a class and set a field member property without referring to the field object explicitly:
public class Employee
{
public Person _person = new Person();
public void DynamicallySetPersonProperty()
{
MemberInfo[] members = this.GetType().GetMembers();
foreach (MemberInfo member in members.Where(a => a.Name == "_person"))
//get the _person field
{
Type type = member.GetType();
PropertyInfo prop = type.GetProperty("Name"); //good, this works, now to set a value for it
//this line does not work - the error is "property set method not found"
prop.SetValue(member, "new name", null);
}
}
}
public class Person
{
public string Name { get; set; }
}
In the answer that I marked as the answer you need to add:
public static bool IsNullOrEmpty(this string source)
{
return (source == null || source.Length > 0) ? true : false;
}
Here's a complete working example:
public class Person
{
public string Name { get; set; }
}
class Program
{
static void PropertySet(object p, string propName, object value)
{
Type t = p.GetType();
PropertyInfo info = t.GetProperty(propName);
if (info == null)
return;
if (!info.CanWrite)
return;
info.SetValue(p, value, null);
}
static void PropertySetLooping(object p, string propName, object value)
{
Type t = p.GetType();
foreach (PropertyInfo info in t.GetProperties())
{
if (info.Name == propName && info.CanWrite)
{
info.SetValue(p, value, null);
}
}
}
static void Main(string[] args)
{
Person p = new Person();
PropertySet(p, "Name", "Michael Ellis");
Console.WriteLine(p.Name);
PropertySetLooping(p, "Name", "Nigel Mellish");
Console.WriteLine(p.Name);
}
}
EDIT: added a looping variant so you could see how to loop through property info objects.
public class Person
{
public string Name { get; set; }
}
public class Employee
{
public Person person = new Person();
public void DynamicallySetPersonProperty()
{
var p = GetType().GetField("person").GetValue(this);
p.GetType().GetProperty("Name").SetValue(p, "new name", null);
}
}
With the following Extension methods that I have created, you can set or get any property value even if they are nested
GetPropertyValue(customObject, "Property.Nested.Child.Name");
or set
SetPropertyValue(customObject, "Property.Nested.Child.Name", "my custom name");
private class TargetProperty
{
public object Target { get; set; }
public PropertyInfo Property { get; set; }
public bool IsValid { get { return Target != null && Property != null; } }
}
private static TargetProperty GetTargetProperty(object source, string propertyName)
{
if (!propertyName.Contains("."))
return new TargetProperty { Target = source, Property = source.GetType().GetProperty(propertyName) };
string[] propertyPath = propertyName.Split('.');
var targetProperty = new TargetProperty();
targetProperty.Target = source;
targetProperty.Property = source.GetType().GetProperty(propertyPath[0]);
for (int propertyIndex = 1; propertyIndex < propertyPath.Length; propertyIndex++)
{
propertyName = propertyPath[propertyIndex];
if (!string.IsNullOrEmpty(propertyName))
{
targetProperty.Target = targetProperty.Property.GetValue(targetProperty.Target, null);
targetProperty.Property = targetProperty.Target.GetType().GetProperty(propertyName);
}
}
return targetProperty;
}
public static bool HasProperty(this object source, string propertyName)
{
return GetTargetProperty(source, propertyName).Property != null;
}
public static object GetPropertyValue(this object source, string propertyName)
{
var targetProperty = GetTargetProperty(source, propertyName);
if (targetProperty.IsValid)
{
return targetProperty.Property.GetValue(targetProperty.Target, null);
}
return null;
}
public static void SetPropertyValue(this object source, string propertyName, object value)
{
var targetProperty = GetTargetProperty(source, propertyName);
if(targetProperty.IsValid)
{
targetProperty.Property.SetValue(targetProperty.Target, value, null);
}
}
And here are a couple of tests for it
[TestFixture]
public class ObjectExtensionsTest
{
private class MockClass
{
public MockClass()
{
Nested = new NestedMockClass();
}
public string Id { get; set; }
public string Name { get; set; }
public string GetOnly { get { return "MockClass"; } }
public string SetOnly { set { } }
public NestedMockClass Nested { get; set; }
}
private class NestedMockClass
{
public string NestedId { get; set; }
public string NestedName { get; set; }
public string NestedGetOnly { get { return "NestedMockClass"; } }
public string NestedSetOnly { set { } }
}
[Test]
public void TestShouldFindProperty()
{
MockClass mockObject = new MockClass();
Assert.IsTrue(mockObject.HasProperty("Id"));
Assert.IsTrue(mockObject.HasProperty("Name"));
Assert.IsTrue(mockObject.HasProperty("GetOnly"));
Assert.IsTrue(mockObject.HasProperty("SetOnly"));
Assert.IsTrue(mockObject.HasProperty("Nested"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedId"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedName"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedGetOnly"));
Assert.IsTrue(mockObject.HasProperty("Nested.NestedSetOnly"));
}
[Test]
public void TestShouldGetPropertyValue()
{
MockClass mockObject = new MockClass();
mockObject.Id = "1";
mockObject.Name = "Name";
mockObject.Nested.NestedId = "NestedId";
mockObject.Nested.NestedName = "NestedName";
Assert.AreEqual(mockObject.Id, mockObject.GetPropertyValue("Id"));
Assert.AreEqual(mockObject.Name, mockObject.GetPropertyValue("Name"));
Assert.AreEqual(mockObject.GetOnly, mockObject.GetPropertyValue("GetOnly"));
Assert.AreEqual(mockObject.Nested.NestedId, mockObject.GetPropertyValue("Nested.NestedId"));
Assert.AreEqual(mockObject.Nested.NestedName, mockObject.GetPropertyValue("Nested.NestedName"));
}
[Test]
public void TestShouldSetPropertyValue()
{
MockClass mockObject = new MockClass();
mockObject.SetPropertyValue("Id", "1");
mockObject.SetPropertyValue("Name", "Name");
mockObject.SetPropertyValue("Nested.NestedId", "NestedId");
mockObject.SetPropertyValue("Nested.NestedName", "NestedName");
Assert.AreEqual(mockObject.Id, "1");
Assert.AreEqual(mockObject.Name, "Name");
Assert.AreEqual(mockObject.Nested.NestedId, "NestedId");
Assert.AreEqual(mockObject.Nested.NestedName, "NestedName");
}
}
Hope you find it useful.
You are trying to set the Name property of your Employee class's _person field. It doesn't have one. Try this:
prop.SetValue(((FieldInfo)member).GetValue(this), "new name", null)
Not sure if you need to cast the first argument like this:
prop.SetValue((Person)((FieldInfo)member).GetValue(this), "new name", null)
This then applies it to the value of the _person field instead.
You a trying to perform SetValue() on the property Name of the variable member that is a MemberInfo object and this proeprty is read only.
Note you do not need to iterate over all memebers and you do not need to get the field _person with reflection as it is defined in the same class as the method DynamicallySetPersonProperty().
So the code shoul read like this.
PropertyInfo property = this._person.GetType().GetProperty("Name");
property.SetValue(this._person, "new name", null);
The first line will fail if _person is null. So you can use reflectiopn to get the type of the field.
FieldInfo field = this.GetType().GetField("_person", BindingFlags.Public);
PropertyInfo property = field.FieldType.GetProperty("Name");
But now accessing this property will still fail if _personis null.
property.Setvalue(field.GetValue(this), "new name", null);
try this:
public static void ApplyPropertyChanges(this object objDest, object objToCopyFrom)
{
if (objDest == null)
throw new ArgumentNullException();
if (objToCopyFrom == null)
throw new ArgumentNullException("objToCopyFrom");
if (objDest.GetType() != objToCopyFrom.GetType())
throw new Exception("Invalid type. Required: \"" + objDest.GetType().ToString() + "\"");
foreach (System.Reflection.PropertyInfo piOrig in objDest.GetType().GetProperties())
{
object editedVal = objToCopyFrom.GetType().GetProperty(piOrig.Name).GetValue(objToCopyFrom, null);
piOrig.SetValue(objDest,
editedVal,
null);
}
}
usage example:
public ActionResult Edit(Team editedTeamData)
{
if (!ModelState.IsValid)
return View();
Team origTeam = (from t in _db.Teams
where t.TeamID == editedTeamData.TeamID
select t).FirstOrDefault();
origTeam.ApplyPropertyChanges(editedTeamData);
_db.SubmitChanges();
return RedirectToAction("Index");
}