DefaultMemberAttribute Class

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.NET Framework Class Library

DefaultMemberAttribute Class

Defines the member of a type that is the default member used by InvokeMember.

System.Object
  System.Attribute
    System.Reflection.DefaultMemberAttribute

Namespace:  System.Reflection
Assembly:  mscorlib (in mscorlib.dll)
[SerializableAttribute]
[AttributeUsageAttribute(AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Interface)]
[ComVisibleAttribute(true)]
public sealed class DefaultMemberAttribute : Attribute

The DefaultMemberAttribute type exposes the following members.

  Name Description
Public method Supported by the XNA Framework Supported by Portable Class Library DefaultMemberAttribute Initializes a new instance of the DefaultMemberAttribute class.
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  Name Description
Public property Supported by the XNA Framework Supported by Portable Class Library MemberName Gets the name from the attribute.
Public property TypeId When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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  Name Description
Public method Supported by the XNA Framework Supported by Portable Class Library Equals Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected method Supported by the XNA Framework Supported by Portable Class Library Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method Supported by the XNA Framework Supported by Portable Class Library GetHashCode Returns the hash code for this instance. (Inherited from Attribute.)
Public method Supported by the XNA Framework Supported by Portable Class Library GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttribute When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method Supported by the XNA Framework Match When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected method Supported by the XNA Framework Supported by Portable Class Library MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method Supported by the XNA Framework Supported by Portable Class Library ToString Returns a string that represents the current object. (Inherited from Object.)
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  Name Description
Explicit interface implemetation Private method _Attribute.GetIDsOfNames Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfo Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfoCount Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.Invoke Provides access to properties and methods exposed by an object. (Inherited from Attribute.)
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A property is imported as an indexer (default indexed property in Visual Basic) if the property has arguments and if the name of the property or one of its accessors matches the name specified by the DefaultMemberAttribute. If the DefaultMemberAttribute is not present on the containing type, then the type does not have an indexer. The C# compiler emits the DefaultMemberAttribute on any type containing an indexer. In C# it is an error to manually attribute a type with the DefaultMemberAttribute if the type also declares an indexer.

The following example uses the DefaultMemberAttribute attribute to make the Age property the default member of the MyClass class.



using System;
using System.Reflection;
using System.IO;

[DefaultMemberAttribute("Age")]   
public class MyClass
{
    public void Name(String s) {}
    public int Age
    {
        get
        {
            return 20;
        }
    }
    public static void Main()
    {
        try
        {
            Type  myType = typeof(MyClass);
            MemberInfo[] memberInfoArray = myType.GetDefaultMembers();
            if (memberInfoArray.Length > 0)
            {
                foreach(MemberInfo memberInfoObj in memberInfoArray)
                {
                    Console.WriteLine("The default member name is: " + memberInfoObj.ToString());
                }
            }
            else
            {
                Console.WriteLine("No default members are available."); 
            }
        }
        catch(InvalidOperationException e)
        {
            Console.WriteLine("InvalidOperationException: " + e.Message);
        }
        catch(IOException e)
        {
            Console.WriteLine("IOException: " + e.Message);
        }
        catch(Exception e)
        {
            Console.WriteLine("Exception: " + e.Message);
        }
    }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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