Hi

Based on my research, .NET did expose the approach to create an EMF, but we
did not provide the encoder to save it into disk, due to the KB below.
http://support.microsoft.com/?id=316563.

So we need to that in GDI/GDI+ unmanaged code.
        [DllImport("gdiplus.dll")]
        private static extern uint GdipEmfToWmfBits (IntPtr _hEmf, uint
_bufferSize,
            byte[] _buffer, int _mappingMode, EmfToWmfBitsFlags _flags);
        [DllImport("gdi32.dll")]
        private static extern IntPtr SetMetaFileBitsEx (uint _bufferSize,
            byte[] _buffer);
        [DllImport("gdi32.dll")]
        private static extern IntPtr CopyMetaFile (IntPtr hWmf,
            string filename);
        [DllImport("gdi32.dll")]
        private static extern bool DeleteMetaFile (IntPtr hWmf);
        [DllImport("gdi32.dll")]
        private static extern bool DeleteEnhMetaFile (IntPtr hEmf);
        private void button4_Click(object sender, System.EventArgs e)
        {
            Graphics g= this.CreateGraphics();
            IntPtr hDC = g.GetHdc();
            Metafile mf = new Metafile(hDC,EmfType.EmfOnly);
            g.ReleaseHdc(hDC);
            g.Dispose();
            g=Graphics.FromImage(mf);
            //Pen p = new Pen(Color.White,5);
            g.DrawArc(Pens.Black,0,0,200,200,0,360);
            //g.DrawImage(Bitmap.FromFile(@"c:\temp\test.bmp"),0,0);
            g.Dispose();
            IntPtr _hEmf= mf.GetHenhmetafile();
            uint _bufferSize = GdipEmfToWmfBits(_hEmf, 0, null, MM_ANISOTROPIC,
                EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);
            byte[] _buffer = new byte[_bufferSize];
            GdipEmfToWmfBits(_hEmf, _bufferSize, _buffer, MM_ANISOTROPIC,
                   EmfToWmfBitsFlags.EmfToWmfBitsFlagsDefault);
            IntPtr hmf = SetMetaFileBitsEx(_bufferSize, _buffer);
            CopyMetaFile(hmf, "C:\\ConvertedMetafile.wmf");
            DeleteMetaFile(hmf);
            DeleteEnhMetaFile(_hEmf);
        }

If you still have any concern I think you would better post in the gdi
newsgroup.
microsoft.public.win32.programmer.gdi

Best regards,

Peter Huang
Microsoft Online Partner Support