从服务器下载文件,图片转PDF,Word转PDF,将PDF合并

　　　　　　using iTextSharp.text;
　　　　　　using iTextSharp.text.pdf;

　　　　　/// <summary>
        /// 图片转成pdf
        /// </summary>
        public static void ConvertJPG2PDF(string jpgfile, string pdf, out string ErrorMsg)
        {
            ErrorMsg = string.Empty;
            try
            {
                iTextSharp.text.Document document = new iTextSharp.text.Document(iTextSharp.text.PageSize.A4, 0f, 0f, 0f, 20f);
                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);
                        image.ScaleAbsoluteWidth(iTextSharp.text.PageSize.A4.Width + 300);
                        image.ScaleAbsoluteHeight(iTextSharp.text.PageSize.A4.Height - 300);
                        image.RotationDegrees = 270f;
                        image.Alignment = iTextSharp.text.Image.ALIGN_MIDDLE;
                        document.Add(image);
                    }
                    document.Close();
                }
            }
            catch (Exception ex)
            {
                Log.WriteLog(ex);
                ErrorMsg = ex.Message;
            }
        }

        /// <summary>
        /// word文档转pdf
        /// </summary>
        public static string WordToPdf(string sourcePath, out string ErrorMsg)
        {
            ErrorMsg = string.Empty;

            Microsoft.Office.Interop.Word.Application application = null;
            Microsoft.Office.Interop.Word.Document document = null;
            string PDFPath = string.Empty;
            if (!File.Exists(sourcePath))
                return string.Empty;
            try
            {
                application = new Microsoft.Office.Interop.Word.Application();
                application.Visible = false;
                document = application.Documents.Open(sourcePath);
                PDFPath = sourcePath.Replace(".doc", ".pdf");//pdf存放位置
                //if (!File.Exists(PDFPath))//存在PDF，不需要继续转换
                document.PageSetup.PaperSize = Microsoft.Office.Interop.Word.WdPaperSize.wdPaperA4;//设置纸张样式为A4纸
                document.PageSetup.Orientation = Microsoft.Office.Interop.Word.WdOrientation.wdOrientPortrait;//排列方式为垂直方向
                //document.PageSetup.TopMargin = 0f;
                //document.PageSetup.BottomMargin = 0f;
                //document.PageSetup.LeftMargin = 0f;
                //document.PageSetup.RightMargin = 0f;
                document.ExportAsFixedFormat(PDFPath, Microsoft.Office.Interop.Word.WdExportFormat.wdExportFormatPDF);
            }
            catch (Exception ex)
            {
                ErrorMsg = ex.Message;
                Log.WriteLog(ex);
                PDFPath = string.Empty;
            }
            finally
            {
                try
                {
                    if (document != null)
                        document.Close();
                    if (application != null)
                        application.Quit();
                }
                catch (Exception ex)
                {
                    Log.WriteLog(ex);
                }
            }
            return PDFPath;
        }

        /// <summary>
        /// 合成pdf文件
        /// </summary>
        /// <param name="fileList">文件名list</param>
        /// <param name="outMergeFile">输出路径</param>
        public static void mergePDFFiles(List<string> fileList, string outMergeFile, out string ErrorMsg)
        {
            ErrorMsg = string.Empty;
            try
            {
                PdfReader reader;
                //Rectangle rec = new Rectangle(0, 0);
                Document document = new Document();
                document.SetMargins(0f, 0f, 0f, 0f);
                PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(outMergeFile, FileMode.Create));
                document.Open();
                PdfContentByte cb = writer.DirectContent;
                PdfImportedPage newPage;
                for (int i = 0; i < fileList.Count; i++)
                {
                    reader = new PdfReader(fileList[i]);
                    int iPageNum = reader.NumberOfPages;
                    for (int j = 1; j <= iPageNum; j++)
                    {
                        document.NewPage();
                        newPage = writer.GetImportedPage(reader, j);
                        cb.AddTemplate(newPage, 0, 0);
                    }
                }
                document.Close();
            }
            catch (Exception ex)
            {
                ErrorMsg = ex.Message;
                Log.WriteLog(ex);
            }
        }

        /// <summary>
        /// 获取文件服务器路径下载到本地
        /// </summary>
        /// <param name="_url"></param>
        /// <param name="ErrorMsg"></param>
        /// <returns></returns>
        public static string Http_GetFile(string _url,string docPath, out string ErrorMsg)
        {
            string FileName = "";
            ErrorMsg = "";
            try
            {
                string url = _url;
                string path = docPath;//路径
                if (Directory.Exists(path) == false)//判断文件夹是否存在
                {
                    Directory.CreateDirectory(path);
                }

                string fn = DateTime.Now.ToString("yyyyMMddHHmmss") + "." + url.Split('.')[url.Split('.').Length - 1];

                if (!File.Exists(path + FileName))//判断文件是否存在
                {
                    File.Create(path + FileName).Close();
                }

                FileName = path + FileName;

                System.Net.WebClient web = new System.Net.WebClient();
                web.Credentials = System.Net.CredentialCache.DefaultCredentials;
                web.DownloadFile(url, path + FileName);
            }
            catch (Exception ex)
            {
                Log.WriteLog(ex);
                ErrorMsg = ex.Message;
            }
            return FileName;
        }