Marshal.QueryInterface Method
Requests a pointer to a specified interface from a COM object.
Namespace: System.Runtime.InteropServices
Assembly: mscorlib (in mscorlib.dll)
Parameters
- pUnk
- Type: System.IntPtr
The interface to be queried.
- iid
- Type: System.Guid
The interface identifier (IID) of the requested interface.
- ppv
- Type: System.IntPtr
When this method returns, contains a reference to the returned interface.
The QueryInterface method exposes the IUnknown::QueryInterface method of a COM object, which attempts to obtain a specific interface pointer. Using QueryInterface on a COM object is the same as performing a cast operation in managed code. Calling an object with this method causes the reference count to increment on the interface pointer before the pointer is returned. Always use Marshal.Release to decrement the reference count once you have finished with the pointer. To obtain an IntPtr value that represents a IUnknown interface pointer, you can call Marshal.GetComInterfaceForObject, Marshal.GetIUnknownForObject, or Marshal.GetIDispatchForObject.
- SecurityCriticalAttribute
requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.
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.
