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Marshal.AddRef Method

Increments the reference count on the specified interface.

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

public static int AddRef(
	IntPtr pUnk
)

Parameters

pUnk
Type: System.IntPtr

The interface reference count to increment.

Return Value

Type: System.Int32
The new value of the reference count on the pUnk parameter.

The common language runtime manages the reference count of a COM object for you, making it unnecessary to use this method directly. In rare cases, such as testing a custom marshaler, you might find it necessary to manipulate an object's lifetime manually. After calling AddRef, you must decrement the reference count by using a method such as Marshal.Release. Do not rely on the return value of AddRef, as it can sometimes be unstable.

You can call Marshal.GetComInterfaceForObject, Marshal.GetIUnknownForObject, or Marshal.GetIDispatchForObject to obtain an IntPtr value that represents an IUnknown interface pointer. You can also use these methods and the AddRef method on managed objects to obtain the COM interfaces represented by the managed object's COM callable wrapper. If you are not familiar with the details of this wrapper type, see COM Callable Wrapper.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

  • SecurityCriticalAttribute 

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

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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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