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Type.GetDefaultMembers Method

Searches for the members defined for the current Type whose DefaultMemberAttribute is set.

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

'Declaration
Public Overridable Function GetDefaultMembers As MemberInfo()

Return Value

Type: System.Reflection.MemberInfo()
An array of MemberInfo objects representing all default members of the current Type.
-or-
An empty array of type MemberInfo, if the current Type does not have default members.

Implements

_Type.GetDefaultMembers

The GetDefaultMembers method does not return members in a particular order, such as alphabetical or declaration order. Your code must not depend on the order in which members are returned, because that order varies.

This method can be overridden by a derived class.

Members include properties, methods, fields, events, and so on.

The following table shows what members of a base class are returned by the Get methods when reflecting on a type.

Member Type

Static

Non-Static

Constructor

No

No

Field

No

Yes. A field is always hide-by-name-and-signature.

Event

Not applicable

The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below.

Method

No

Yes. A method (both virtual and non-virtual) can be hide-by-name or hide-by-name-and-signature.

Nested Type

No

No

Property

Not applicable

The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below.

  1. Hide-by-name-and-signature considers all of the parts of the signature, including custom modifiers, return types, parameter types, sentinels, and unmanaged calling conventions. This is a binary comparison.

  2. For reflection, properties and events are hide-by-name-and-signature. If you have a property with both a get and a set accessor in the base class, but the derived class has only a get accessor, the derived class property hides the base class property, and you will not be able to access the setter on the base class.

  3. Custom attributes are not part of the common type system.

If the current Type represents a constructed generic type, this method returns the MemberInfo objects with the type parameters replaced by the appropriate type arguments. For example, if class C<T> has a property P that returns T, calling GetDefaultMembers on C<int> returns int P in C# (Property P As Integer in Visual Basic).

If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the members of the class constraint, or the members of Object if there is no class constraint.

The following example obtains the default member information of MyClass and displays the default members.

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]

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 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

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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