C#将jpg转换为pdf的方法

void ConvertJPG2PDF(string jpgfile,string pdf)
{
 var document = new Document(iTextSharp.text.PageSize.A4,25,25);
 using (var stream = new FileStream(pdf,FileMode.Create,FileAccess.Write,FileShare.None))
 {
  PdfWriter.GetInstance(document,stream);
  document.Open();
  using (var imageStream = new FileStream(jpgfile,FileMode.Open,FileAccess.Read,FileShare.ReadWrite))
  {
   var image = Image.GetInstance(imageStream);
   if (image.Height > iTextSharp.text.PageSize.A4.Height - 25)
   {
    image.ScaleToFit(iTextSharp.text.PageSize.A4.Width - 25,iTextSharp.text.PageSize.A4.Height - 25);
   }
   else if (image.Width > iTextSharp.text.PageSize.A4.Width - 25)
   {
    image.ScaleToFit(iTextSharp.text.PageSize.A4.Width - 25,iTextSharp.text.PageSize.A4.Height - 25);
   }
   image.Alignment = iTextSharp.text.Image.ALIGN_MIDDLE;
   document.Add(image);
  }
 
  document.Close();
 }
}