Type.GetDefaultMembers Method
Definition
Important
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Searches for the members defined for the current Type whose DefaultMemberAttribute is set.
public:
virtual cli::array <System::Reflection::MemberInfo ^> ^ GetDefaultMembers();public virtual System.Reflection.MemberInfo[] GetDefaultMembers ();abstract member GetDefaultMembers : unit -> System.Reflection.MemberInfo[]
override this.GetDefaultMembers : unit -> System.Reflection.MemberInfo[]Public Overridable Function GetDefaultMembers () As MemberInfo()Returns
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
Examples
The following example obtains the default member information of MyClass and displays the default members.
using namespace System;
using namespace System::Reflection;
using namespace System::IO;
[DefaultMemberAttribute("Age")]
public ref class MyClass
{
public:
void Name( String^ s ){}
property int Age
{
int get()
{
return 20;
}
}
};
int main()
{
try
{
Type^ myType = MyClass::typeid;
array<MemberInfo^>^memberInfoArray = myType->GetDefaultMembers();
if ( memberInfoArray->Length > 0 )
{
System::Collections::IEnumerator^ myEnum = memberInfoArray->GetEnumerator();
while ( myEnum->MoveNext() )
{
MemberInfo^ memberInfoObj = safe_cast<MemberInfo^>(myEnum->Current);
Console::WriteLine( "The default member name is: {0}", memberInfoObj );
}
}
else
{
Console::WriteLine( "No default members are available." );
}
}
catch ( InvalidOperationException^ e )
{
Console::WriteLine( "InvalidOperationException: {0}", e->Message );
}
catch ( IOException^ e )
{
Console::WriteLine( "IOException: {0}", e->Message );
}
catch ( Exception^ e )
{
Console::WriteLine( "Exception: {0}", e->Message );
}
}
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);
}
}
}
open System
open System.Reflection
open System.IO
[<DefaultMemberAttribute "Age">]
type MyClass() =
member _.Name(s: string) = ()
member _.Age
with get () =
20
try
let myType = typeof<MyClass>
let memberInfoArray = myType.GetDefaultMembers()
if memberInfoArray.Length > 0 then
for memberInfoObj in memberInfoArray do
printfn $"The default member name is: {memberInfoObj}"
else
printfn "No default members are available."
with
| :? InvalidOperationException as e ->
printfn $"InvalidOperationException: {e.Message}"
| :? IOException as e ->
printfn $"IOException: {e.Message}"
| e ->
printfn $"Exception: {e.Message}"
Imports System.Reflection
Imports System.IO
<DefaultMemberAttribute("Age")> Public Class [MyClass]
Public Sub Name(ByVal s As String)
End Sub
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
End Class
Remarks
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. |
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.
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.
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.
