There are multiple implementations of IDispatch available for you to expose dual interfaces and dispinterfaces to COM. Attach this attribute to a class or an assembly to specify which IDispatch implementation to use. If you apply this attribute to an assembly, it applies to all classes within that assembly. For a list of available IDispatch implementations, see IDispatchImplType . public sealed class IDispatchImplAttribute : Attribute { // Public Constructors public IDispatchImplAttribute (IDispatchImplType implType ); public IDispatchImplAttribute (short implType ); // Public Instance Properties public IDispatchImplType Value {get; } } HierarchySystem.Object System.Attribute IDispatchImplAttribute Valid OnAssembly, Class |