DefaultMemberAttribute Class
Defines the member of a type that is the default member used by InvokeMember.
Assembly: mscorlib (in mscorlib.dll)
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.
Imports System Imports System.Reflection Imports System.IO Imports Microsoft.VisualBasic <DefaultMemberAttribute("Age")> Public Class [MyClass] Public Sub Name(ByVal s As String) End Sub 'Name Public ReadOnly Property Age() As Integer Get Return 20 End Get End Property Public Shared Sub Main() Try Dim myType As Type = GetType([MyClass]) Dim memberInfoArray As MemberInfo() = myType.GetDefaultMembers() If memberInfoArray.Length > 0 Then Dim memberInfoObj As MemberInfo For Each memberInfoObj In memberInfoArray Console.WriteLine("The default member name is: " + memberInfoObj.ToString()) Next memberInfoObj Else Console.WriteLine("No default members are available.") End If Catch e As InvalidOperationException Console.WriteLine("InvalidOperationException: " + e.Message) Catch e As IOException Console.WriteLine("IOException: " + e.Message) Catch e As Exception Console.WriteLine("Exception: " + e.Message) End Try End Sub 'Main End Class '[MyClass]
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The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.