RESOLUTION
To add a metafile to the Clipboard so that it is visible to
other applications, you must use the CF_ENHMETAFILE format. Support for this
format is provided through the
DataObject class with the
DataFormats.EnhancedMetafile method. Unfortunately, limitations in the current implementation
of the .NET Framework prevent this from being a viable solution. Therefore, you
must gain interoperability with Win32
Clipboard application programming interfaces (APIs) to resolve this
problem.
The code samples that follow demonstrate how to add a
metafile to the Clipboard so that it is visible to other applications.
Microsoft Visual Basic .NET Sample
Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices
Public Class ClipboardMetafileHelper
<DllImport("user32.dll", EntryPoint:="OpenClipboard", _
SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function OpenClipboard(ByVal hWnd As IntPtr) As Boolean
End Function
<DllImport("user32.dll", EntryPoint:="EmptyClipboard", _
SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function EmptyClipboard() As Boolean
End Function
<DllImport("user32.dll", EntryPoint:="SetClipboardData", _
SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function SetClipboardData(ByVal uFormat As Integer, ByVal hWnd As IntPtr) As IntPtr
End Function
<DllImport("user32.dll", EntryPoint:="CloseClipboard", _
SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function CloseClipboard() As Boolean
End Function
<DllImport("gdi32.dll", EntryPoint:="CopyEnhMetaFileA", _
SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function CopyEnhMetaFile(ByVal hemfSrc As IntPtr, ByVal hNULL As IntPtr) As IntPtr
End Function
<DllImport("gdi32.dll", EntryPoint:="DeleteEnhMetaFile", _
SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function DeleteEnhMetaFile(ByVal hemfSrc As IntPtr) As Boolean
End Function
' Metafile mf is set to a state that is not valid inside this function.
Public Shared Function PutEnhMetafileOnClipboard(ByVal hWnd As IntPtr, ByVal mf As Metafile) As Boolean
Dim bResult As New Boolean()
bResult = False
Dim hEMF, hEMF2 As IntPtr
hEMF = mf.GetHenhmetafile() ' invalidates mf
If Not hEMF.Equals(New IntPtr(0)) Then
hEMF2 = CopyEnhMetaFile(hEMF, New IntPtr(0))
If Not hEMF2.Equals(New IntPtr(0)) Then
If OpenClipboard(hWnd) Then
If EmptyClipboard() Then
Dim hRes As IntPtr
hRes = SetClipboardData(14, hEMF2) ' 14 == CF_ENHMETAFILE
bResult = hRes.Equals(hEMF2)
CloseClipboard()
End If
End If
End If
DeleteEnhMetaFile(hEMF)
End If
Return bResult
End Function
End Class
'You can call this function with code that is similar to the following code:
Dim mf As New Metafile("filename.emf")
ClipboardMetafileHelper.PutEnhMetafileOnClipboard(me.Handle,mf)
Microsoft Visual C# .NET Sample
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
public class ClipboardMetafileHelper
{
[DllImport("user32.dll")]
static extern bool OpenClipboard(IntPtr hWndNewOwner);
[DllImport("user32.dll")]
static extern bool EmptyClipboard();
[DllImport("user32.dll")]
static extern IntPtr SetClipboardData(uint uFormat, IntPtr hMem);
[DllImport("user32.dll")]
static extern bool CloseClipboard();
[DllImport("gdi32.dll")]
static extern IntPtr CopyEnhMetaFile(IntPtr hemfSrc, IntPtr hNULL);
[DllImport("gdi32.dll")]
static extern bool DeleteEnhMetaFile(IntPtr hemf);
// Metafile mf is set to a state that is not valid inside this function.
static public bool PutEnhMetafileOnClipboard( IntPtr hWnd, Metafile mf )
{
bool bResult = false;
IntPtr hEMF, hEMF2;
hEMF = mf.GetHenhmetafile(); // invalidates mf
if( ! hEMF.Equals( new IntPtr(0) ) )
{
hEMF2 = CopyEnhMetaFile( hEMF, new IntPtr(0) );
if( ! hEMF2.Equals( new IntPtr(0) ) )
{
if( OpenClipboard( hWnd ) )
{
if( EmptyClipboard() )
{
IntPtr hRes = SetClipboardData( 14 /*CF_ENHMETAFILE*/, hEMF2 );
bResult = hRes.Equals( hEMF2 );
CloseClipboard();
}
}
}
DeleteEnhMetaFile( hEMF );
}
return bResult;
}
}
//You can call this function with code that is similar to the following code:
Metafile mf = new Metafile( "filename.emf" );
ClipboardMetafileHelper.PutEnhMetafileOnClipboard(this.Handle, mf );