This documentation is archived and is not being maintained.

IDispatchImplAttribute Class

NOTE: This API is now obsolete.

Indicates which IDispatch implementation the common language runtime uses when exposing dual interfaces and dispinterfaces to COM.

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

[AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class, Inherited = false)]
[ObsoleteAttribute("This attribute is deprecated and will be removed in a future version.", 
public sealed class IDispatchImplAttribute : Attribute

You can apply this attribute to classes or assemblies.

This attribute should only be set when an explicit implementation is required. When you set the attribute to CompatibleImpl, the IDispatch implementation is supplied by passing the type information for the object to COM's CreateStdDispatch API. When you set the attribute to InternalImpl, the IDispatch implementation is supplied by the common language runtime. Setting the attribute to SystemDefinedImpl allows the runtime to choose the appropriate implementation. When using the attribute on an assembly, the attribute applies to all classes defined within the assembly. When using the attribute on an individual class, the attribute applies only to the interfaces exposed by that class and overrides any assembly-level setting.

The following example demonstrates how to apply IDispatchImplAttribute to select the IDispatch implementation supplied by the common language runtime.

using System;
using System.Runtime.InteropServices;
// by default all classes in this assembly will use COM implementaion 

namespace MyNamespace
	// But this class will use runtime implementaion
	class MyClass


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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.

.NET Framework

Supported in: 1.1, 1.0
Obsolete (compiler warning) in 3.5
Obsolete (compiler warning) in 3.5 SP1
Obsolete (compiler warning) in 3.0
Obsolete (compiler warning) in 3.0 SP1
Obsolete (compiler warning) in 3.0 SP2
Obsolete (compiler warning) in 2.0
Obsolete (compiler warning) in 2.0 SP1
Obsolete (compiler warning) in 2.0 SP2