使用PdfSharp将多个TIFF图像转换为PDF

Question

我正在ASP.NET和PdfSharp PDF库中使用WebSite。我有一个包含3页的tiff文档图像，我想将所有3个tiff页转换为1个具有3页的PDF文件。

请告诉我该怎么办？

    PdfDocument doc = new PdfDocument();
    System.Drawing.Image img2 = System.Drawing.Image.FromFile(@"C:\File\0.tiff"); 
    Guid objGuid = img2.FrameDimensionsList[0];
    FrameDimension objDimension = new FrameDimension(objGuid);
    int pageCount = (img2.GetFrameCount(objDimension));
    pageCount--;
    for (int i = 0; i <= pageCount; i++)
    {
        PdfPage page = doc.AddPage();
        XGraphics xgr = XGraphics.FromPdfPage(page);
        img2.SelectActiveFrame(objDimension, i);
        XImage img = XImage.FromGdiPlusImage(img2);
        page.Width = img.PointWidth;
        page.Height = img.PointHeight;
        xgr.DrawImage(img, 0, 0);
    } 
    img2.Dispose();
    doc.Save(@"C:\File\0.pdf");
    doc.Close();