//excel转换
                Workbook workbook = new Workbook(HttpContext.Current.Server.MapPath(docpath + "/" + newFileName + sExtension));//找到转换文件
                string newFilePath = docpath + "NewFile/";
                string newuploadPath = HttpContext.Current.Server.MapPath(newFilePath);//找到转换后文件所存放的路径
                string newfileName = newFileName + ".pdf";
                string err = "";
                if (!Directory.Exists(newuploadPath))//没有此文件夹直接创建
                {
                    Directory.CreateDirectory(newuploadPath);
                }
                workbook.Save(HttpContext.Current.Server.MapPath(newFilePath + newfileName), Aspose.Cells.SaveFormat.Pdf);//转换中



 //word转换
                Aspose.Words.Document doc = new Aspose.Words.Document(HttpContext.Current.Server.MapPath(docpath + "/" + newFileName + sExtension));
                string newFilePath = docpath + "NewFile/";
                string newuploadPath = HttpContext.Current.Server.MapPath(newFilePath);
                string newfileName = newFileName + ".pdf";

                string err = "";
                if (!Directory.Exists(newuploadPath))
                {
                    Directory.CreateDirectory(newuploadPath);
                }
                doc.Save(HttpContext.Current.Server.MapPath(newFilePath + newfileName), Aspose.Words.SaveFormat.Pdf);


 //ppt转换
                Presentation pres = new Presentation(HttpContext.Current.Server.MapPath(docpath + "/" + newFileName + sExtension));
                string newFilePath = docpath + "NewFile/";
                string newuploadPath = HttpContext.Current.Server.MapPath(newFilePath);
                string newfileName = newFileName + ".pdf";
                string err = "";
                if (!Directory.Exists(newuploadPath))
                {
                    Directory.CreateDirectory(newuploadPath);
                }
                pres.Save(HttpContext.Current.Server.MapPath(newFilePath + newfileName), Aspose.Slides.Export.SaveFormat.Pdf);