ManagedToNativeComInteropStubAttribute Class

Definition

Namespace:

System.Runtime.InteropServices

Assembly:

System.Runtime.InteropServices.dll

Source:

ManagedToNativeComInteropStubAttribute.cs

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

public ref class ManagedToNativeComInteropStubAttribute sealed : Attribute

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

[<System.AttributeUsage(System.AttributeTargets.Method, AllowMultiple=false, Inherited=false)>]
type ManagedToNativeComInteropStubAttribute = class
    inherit Attribute

Public NotInheritable Class ManagedToNativeComInteropStubAttribute
Inherits Attribute

Inheritance

Object

Attribute

ManagedToNativeComInteropStubAttribute

Attributes

AttributeUsageAttribute

Remarks

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.

Note

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:

[ComImport]  
interface IMyInterface  
{  
    [ManagedToNativeComInteropStubAttribute(typeof(TestStubClass),  
              "ForwardTestStub")]  
    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) {…}  
}  

Constructors

ManagedToNativeComInteropStubAttribute(Type, String)

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

Properties

ClassType	Gets the class that contains the required stub method.
MethodName	Gets the name of the stub method.
TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)