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ManagedToNativeComInteropStubAttribute Class

Provides support for user customization of interop stubs in managed-to-COM interop scenarios.


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

[AttributeUsageAttribute(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
public sealed class ManagedToNativeComInteropStubAttribute : Attribute

The ManagedToNativeComInteropStubAttribute type exposes the following members.

Public methodManagedToNativeComInteropStubAttributeInitializes a new instance of the ManagedToNativeComInteropStubAttribute class with the specified class type and method name.

Public propertyClassTypeGets the class that contains the required stub method.
Public propertyMethodNameGets the name of the stub method.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)

Public methodEqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

This attribute enables interop developers who have knowledge about marshaling and the inner workings of interop calls to do the following:

  • Take advantage of customized interop stubs at build time instead of run time.

  • Debug customized interop stubs.

  • Provide marshaling capabilities within a stub that the runtime does not provide.

  • Provide user-specific method dispatch capabilities.

You apply the attribute on a method in an interface to specify a corresponding stub method for managed-to-native COM interop.

If this attribute is encountered during run time, the common language runtime does not dynamically generate an interop stub. Instead, it invokes the custom stub that was created at build time.

The ManagedToNativeComInteropStubAttribute attribute has the following characteristics:

  • The attribute can be used only on methods from interfaces that are marked [ComImport]. If the attribute is applied to non-interface types, it is ignored by the runtime.

  • The attribute can be used only once on the same method in an interface. If it is used more than once, the compiler generates a duplicated attribute error.

  • The attribute is not inheritable from a base interface. Derived interfaces must explicitly assign the attribute.

  • The assembly that contains the attributed method must also contain the customized stub.

Overloaded stub methods are valid. Although you specify only the type and the name of the stub method, the runtime will discover the corresponding stub. It does this by examining all the arguments on the interface method, and then performing full signature matching by using an explicit this pointer.

It is also possible for multiple methods in an interface to share the same stub method; however, you should be careful when you use shared stubs.


Stub methods must be static.

You could inform the runtime to use a customized interop stub at build time instead of run time with the following C# code:

interface IMyInterface
    void GetString (string arg);

You could then use the following code to declare the corresponding stub method:

class TestStubClass
    internal static void ForwardTestStub(IMyInterface thisObject,
             string arg) {…}

.NET Framework

Supported in: 4

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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