Artikel
11/18/2011

Type.GetProperty Method (String)

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Searches for the public property with the specified name.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Function GetProperty ( _
    name As String _
) As PropertyInfo

public PropertyInfo GetProperty(
    string name
)

Parameters

name
Type: System.String
The String containing the name of the public property to get.

Return Value

Type: System.Reflection.PropertyInfo
A PropertyInfo object representing the public property with the specified name, if found; otherwise, nulla null reference (Nothing in Visual Basic).

Exceptions

Exception	Condition
AmbiguousMatchException	More than one property is found with the specified name. See Remarks.
ArgumentNullException	name is nulla null reference (Nothing in Visual Basic).

Remarks

The search for name is case-sensitive. The search includes public static and public instance properties.

A property is considered public to reflection if it has at least one accessor that is public. Otherwise the property is considered private, and you must use BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static (in Visual Basic, combine the values using Or) to get it.

If the current Type represents a constructed generic type, this method returns the PropertyInfo with the type parameters replaced by the appropriate type arguments.

If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the properties of the class constraint.

Situations in which AmbiguousMatchException occurs include the following:

A type contains two indexed properties that have the same name but different numbers of parameters. To resolve the ambiguity, use an overload of the GetProperty method that specifies parameter types.
A derived type declares a property that hides an inherited property with the same name, by using the new modifier (Shadows in Visual Basic). To resolve the ambiguity, use the GetProperty(String, BindingFlags) method overload and include BindingFlags.DeclaredOnly to restrict the search to members that are not inherited.

Indexers and Default Properties

Visual Basic 2005, Visual C# 2005, and Visual C++ 2005 have simplified syntax for accessing indexed properties and allow one indexed property to be a default for its type. For example, if the variable myList refers to a List<T>, the syntax myList[3] (myList(3) in Visual Basic) retrieves the element with the index of 3. You can overload the property.

In C#, this feature is called an indexer and cannot be refered to by name. By default, a C# indexer appears in metadata as an indexed property named "Item". However, a class library developer can use the IndexerNameAttribute attribute to change the name of the indexer in the metadata. For example, the String class has an indexer named Chars. Indexed properties created using languages other than C# can have names other than Item, as well.

To determine whether a type has a default property, use the GetCustomAttributes(Type, Boolean) method to test for the DefaultMemberAttribute attribute. If the type has DefaultMemberAttribute, the MemberName property returns the name of the default property.

Examples

The following example retrieves the Type object of a user-defined class, retrieves a property of that class, and displays the property name.

Note:
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control.

Imports System.Reflection
Class MyClass1
   Private myProperty1 As Integer
   ' Declare MyProperty.

   Public Property MyProperty() As Integer
      Get
         Return myProperty1
      End Get
      Set(ByVal Value As Integer)
         myProperty1 = Value
      End Set
   End Property
End Class 'MyClass1

Public Class Example
   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Try
         ' Get Type Object corresponding to MyClass.
         Dim myType As Type = GetType(MyClass1)
         ' Get PropertyInfo object by passing property name.
         Dim myPropInfo As PropertyInfo = myType.GetProperty("MyProperty")
         ' Display Name propety to console.
         outputBlock.Text += String.Format("The {0} property exists in MyClass.", myPropInfo.Name) & vbCrLf
      Catch e As NullReferenceException
         outputBlock.Text += String.Format("The property does not exist in MyClass.", e.Message.ToString()) & vbCrLf
      End Try
   End Sub 'Main
End Class 'MyTypeClass


using System;
using System.Reflection;

class MyClass
{
   private int myProperty;
   // Declare MyProperty.
   public int MyProperty
   {
      get
      {
         return myProperty;
      }
      set
      {
         myProperty = value;
      }
   }
}
public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      try
      {
         // Get the Type object corresponding to MyClass.
         Type myType = typeof(MyClass);
         // Get the PropertyInfo object by passing the property name.
         PropertyInfo myPropInfo = myType.GetProperty("MyProperty");
         // Display the property name.
         outputBlock.Text += String.Format("The {0} property exists in MyClass.", myPropInfo.Name) + "\n";
      }
      catch (NullReferenceException e)
      {
         outputBlock.Text += "The property does not exist in MyClass." + e.Message + "\n";
      }
   }
}

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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