var path = string.Empty;
                if (writer.PageNumber == 1)
                {
                    path = AppSetting.ApiSiteUrl+ "/Images/ContractTitle.png";
                }
                else
                {
                    path = AppSetting.ApiSiteUrl+ "/Images/ContractDetail.png";
                }
                Uri url = new Uri(path);
                iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(url);
              
                var chunk = new Chunk(image, -200, 0,false);
                Phrase header = new Phrase(chunk);
                //Phrase header = new Phrase("11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111");
                Phrase footer = new Phrase("第" + (writer.PageNumber+1) + "页", font);
                PdfContentByte cb = writer.DirectContent;

                //模版 显示总共页数
                //cb.AddTemplate(tpl, document.Right - 54 + document.LeftMargin, document.Bottom - 8);//调节模版显示的位置

                //页眉显示的位置
                ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, header,
                       document.Right - 140 + document.LeftMargin, document.Top + 10, 0);

                //页脚显示的位置
                ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, footer,
                       document.Right - 60 + document.LeftMargin, document.Bottom - 10, 0);