Marshal.CreateWrapperOfType Method (Object, Type)


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

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

Public Shared Function CreateWrapperOfType (
	o As Object,
	t As Type
) As Object


Type: System.Object

The object to be wrapped.

Type: System.Type

The type of wrapper to create.

Return Value

Type: System.Object

The newly wrapped object that is an instance of the desired type.

Exception Condition

t must derive from __ComObject.


t is a Windows Runtime type.


The t parameter is null.


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

CreateWrapperOfType converts one COM class type, typically the generic __ComObject type, to another COM class type. The input COM object, represented by parameter o, is a Runtime Callable Wrapper (RCW).

Both the t and o parameters must be classes whose signatures are attributed with System.Runtime.InteropServices.ComImportAttribute. 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. Since 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.


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

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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