C# JPG转PDF

 需先引用 itextsharp.dll
 //方法一
        /// <summary>
        /// JPG转PDF
        /// </summary>
        /// <param name="jpgfile">图片路径</param>
        /// <param name="pdf">生成的PDF路径</param>
        /// <param name="pageSize">A4，A5</param>
        /// <param name="Vertical">True:纵向，False横向</param>
        public void ConvertJPG2PDF(string jpgfile, string pdf, string pageSize, bool Vertical = true)
        {
            float width = 0, height = 0;
            Document document;

            #region 根据纸张大小，纵横向，设置画布长宽
            if (pageSize.ToUpper() == "A4")
            {
                if (Vertical)//纵向
                {
                    width = iTextSharp.text.PageSize.A4.Width;
                    height = iTextSharp.text.PageSize.A4.Height;
                }
                else//横向
                {
                    width = iTextSharp.text.PageSize.A4.Height;
                    height = iTextSharp.text.PageSize.A4.Width;
                }
            }
            else if (pageSize.ToUpper() == "A5")
            {
                if (Vertical)
                {
                    width = iTextSharp.text.PageSize.A5.Width;
                    height = iTextSharp.text.PageSize.A5.Height;
                }
                else
                {
                    width = iTextSharp.text.PageSize.A5.Height;
                    height = iTextSharp.text.PageSize.A5.Width;
                }
            }

            iTextSharp.text.Rectangle pageSizeNew = new iTextSharp.text.Rectangle(width, height);
            document = new Document(pageSizeNew);
            #endregion 


            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 = iTextSharp.text.Image.GetInstance(imageStream);

                    //缩放图像比例
                    image.ScaleToFit(width, height);
                    image.SetAbsolutePosition(0, 0);

                    image.Alignment = iTextSharp.text.Image.ALIGN_MIDDLE;

                    document.Add(image);
                }
                document.Close();

            }

        }

//方法二
/// <summary>
        /// jpg转PDF
        /// </summary>
        /// <param name="pdfPath">pdf存放路径</param>
        /// <param name="jpegPath">jpg路径</param>
        /// <returns></returns>
        private bool jpegTopdf(string pdfPath, string jpegPath)
        {
            try
            {
                System.Drawing.Image B = System.Drawing.Image.FromFile(jpegPath);
                System.Drawing.Bitmap image = new System.Drawing.Bitmap(B);
                B.Dispose();

                Document document = new Document();
                //document.SetPageSize(new iTextSharp.text.Rectangle(image.Width + 72f, image.Height + 72f));
                document.SetPageSize(new iTextSharp.text.Rectangle(image.Width, image.Height));
                PdfWriter write = PdfWriter.GetInstance(document, new FileStream(pdfPath, FileMode.OpenOrCreate, FileAccess.Write));
                document.Open();
                iTextSharp.text.Image jpg;

                jpg = iTextSharp.text.Image.GetInstance(image, ImageFormat.Jpeg);
                document.NewPage();
                document.Add(jpg);

                if (document != null && document.IsOpen())
                {
                    document.Close();
                }
                if (write != null)
                {
                    write.Close();
                }
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }