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SafeHandle.SetHandle Method

Note: This method is new in the .NET Framework version 2.0.

Sets the handle to the specified pre-existing handle.

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

'Declaration
Protected Sub SetHandle ( _
	handle As IntPtr _
)
'Usage
Dim handle As IntPtr

Me.SetHandle(handle)
protected void SetHandle (
	IntPtr handle
)
protected function SetHandle (
	handle : IntPtr
)

Parameters

handle

The pre-existing handle to use.

Use the SetHandle method only if you need to support a pre-existing handle (for example, if the handle is returned in a structure) because the .NET Framework COM interop infrastructure does not support marshaling output handles in a structure.

The following example demonstrates how to implement the SetHandle method. To reliably set a handle to a specified pre-existing handle, you must ensure that the allocation of the native handle and the subsequent recording of that handle within a SafeHandle object is atomic. Any failure between these operations (such as a thread abort or out of memory exception) will result in the native handle being leaked. The code example that follows shows how reliability can be achieved using a constrained execution region.

<StructLayout(LayoutKind.Sequential)> _
Structure MyStruct
    Public m_outputHandle As IntPtr
End Structure 'MyStruct


NotInheritable Class MySafeHandle
    Inherits SafeHandle

    ' Called by P/Invoke when returning SafeHandles
    Public Sub New()
        MyBase.New(IntPtr.Zero, True)

    End Sub


    Public Function AllocateHandle() As MySafeHandle
        ' Allocate SafeHandle first to avoid failure later.
        Dim sh As New MySafeHandle()

        RuntimeHelpers.PrepareConstrainedRegions()
        Try
        Finally
            Dim myStruct As New MyStruct()
            NativeAllocateHandle(myStruct)
            sh.SetHandle(myStruct.m_outputHandle)
        End Try

        Return sh

    End Function



Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0
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