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Marshal::CreateWrapperOfType<T, TWrapper> Method (T)

[Supported in the .NET Framework 4.5.1 and later versions]

Wraps the specified COM object in an object of the specified type.

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

generic<typename T, typename TWrapper>
static TWrapper CreateWrapperOfType(
	T o

Type Parameters


The type of object to wrap.


The type of object to return.


Type: T

The object to be wrapped.

Return Value

Type: TWrapper
The newly wrapped object.


T must derive from __ComObject.


T is a Windows Runtime type.


o cannot be converted to the TWrapper because it does not support all required interfaces.

CreateWrapperOfType<T, TWrapper>(T) converts a COM object of type T to the TWrapper COM class type. The input COM object, represented by parameter o, is a Runtime Callable Wrapper (RCW).

Both the T generic type parameter and the o parameter must be classes whose signatures are attributed with the System.Runtime.InteropServices::ComImportAttribute attribute. The Tlbimp.exe (Type Library Importer) tool applies this attribute for you when it imports a type library. If you create the RCW manually in source code, you should apply this attribute to the managed signature that represents the original coclass to signify its COM origins.

Tlbimp.exe imports a COM coclass as a managed class and an interface. The coclass interface has the same name as the original coclass, and the managed class has the original coclass name appended with "Class". For example, a coclass called MyCoclass becomes a coclass interface called MyCoclass and a managed class called MyCoclassClass. Because T must be a class, not an interface, be sure to specify the managed class (MyCoclassClass) and not the coclass interface.


You lose the identity of the input COM object, because a new RCW instance wraps the IUnknown pointer exposed by the original RCW.

.NET Framework

Supported in: 4.6, 4.5.1

Supported in: Windows Phone 8.1

  • SecurityCriticalAttribute 

    requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Windows Phone 8.1

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

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