ASP.NET如何下载PDF文件

.htm, .html     Response.ContentType = "text/HTML"; .txt    Response.ContentType = "text/plain";
.doc, .rtf, .docx    Response.ContentType = "Application/msword";
.xls, .xlsx    Response.ContentType = "Application/x-msexcel";
.jpg, .jpeg    Response.ContentType = "image/jpeg";
.gif    Response.ContentType =  "image/GIF";
.pdf    Response.ContentType = "application/pdf";

 protected void Button1_Click(object sender, EventArgs e) 
     { 
         string path; 
         try 
         { 
             path = Request.PhysicalApplicationPath + "/" + Session["pdfpath"].ToString() + "/PDF/" + Session["mlmc"].ToString() + ".pdf"; 
         } 
         catch (Exception) 
         { 
             return; 
         } 
         System.IO.Stream iStream = null; 
         byte[] buffer = new Byte[10000]; 
         int length; 
         long dataToRead; 
         string filename = Session["mlmc"].ToString() + ".pdf"; 
  
         try 
         { 
             iStream = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read); 
             dataToRead = iStream.Length; 
             Response.Clear(); 
             Response.ClearHeaders(); 
             Response.ClearContent(); 
             Response.ContentType = "application/pdf"; //文件类型 
             Response.AddHeader("Content-Length", dataToRead.ToString());//添加文件长度，进而显示进度 
             Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8)); 
             while (dataToRead > 0) 
             { 
                 if (Response.IsClientConnected) 
                 { 
                     length = iStream.Read(buffer, 0, 10000); 
                     Response.OutputStream.Write(buffer, 0, length); 
                     Response.Flush(); 
  
                     buffer = new Byte[10000]; 
                     dataToRead = dataToRead - length; 
                 } 
                 else 
                 { 
                     dataToRead = -1; 
                 } 
             } 
              
         } 
         catch (Exception ex) 
         { 
             Response.Write("文件下载时出现错误!"); 
         } 
         finally 
         { 
             if (iStream != null) 
             { 
                 iStream.Close(); 
             } 
             //结束响应，否则将导致网页内容被输出到文件，进而文件无法打开 
             Response.End(); 
         }         
     }