ASP.NET 實現PDF文件下載[轉]

本文介紹了一種在ASP.NET中下載文件的方法。
方法一：可能是最簡單的、最短的方式：

1  Response.ContentType = "application/pdf";
2  Response.AppendHeader("Content-Disposition", "attachment; filename=MyFile.pdf");
3  Response.TransmitFile(Server.MapPath("~/Files/MyFile.pdf"));
4  Response.End();

  第一步是設置文檔內容的類型，上面的例子是下載一個.PDF格式的文件。下面是最常用的一些文檔內容類型：

 .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";

方法二：解決.PDF文件較大時，可能導致所下載的PDF文件無法打開的方案

 1     protected void Button1_Click(object sender, EventArgs e)  
 2     {  
 3         string path;  
 4         try  
 5         {  
 6             path = Request.PhysicalApplicationPath + "/" + Session["pdfpath"].ToString() + "/PDF/" + Session["mlmc"].ToString() + ".pdf";  
 7         }  
 8         catch (Exception)  
 9         {  
10             return;  
11         }  
12         System.IO.Stream iStream = null;  
13         byte[] buffer = new Byte[10000];  
14         int length;  
15         long dataToRead;  
16         string filename = Session["mlmc"].ToString() + ".pdf";  
17   
18         try  
19         {  
20             iStream = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);  
21             dataToRead = iStream.Length;  
22             Response.Clear();  
23             Response.ClearHeaders();  
24             Response.ClearContent();  
25             Response.ContentType = "application/pdf"; //文件類型  
26             Response.AddHeader("Content-Length", dataToRead.ToString());//添加文件長度，進而顯示進度  
27             Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8));  
28             while (dataToRead > 0)  
29             {  
30                 if (Response.IsClientConnected)  
31                 {  
32                     length = iStream.Read(buffer, 0, 10000);  
33                     Response.OutputStream.Write(buffer, 0, length);  
34                     Response.Flush();  
35   
36                     buffer = new Byte[10000];  
37                     dataToRead = dataToRead - length;  
38                 }  
39                 else  
40                 {  
41                     dataToRead = -1;  
42                 }  
43             }  
44               
45         }  
46         catch (Exception ex)  
47         {  
48             Response.Write("文件下載時出現錯誤!");  
49         }  
50         finally  
51         {  
52             if (iStream != null)  
53             {  
54                 iStream.Close();  
55             }  
56             //結束響應，否則將導致網頁內容被輸出到文件，進而文件無法打開  
57             Response.End();  
58         }          
59     }  

  通過以上代碼，可在瀏覽器中打開一個“打開/保存”對話框來下載並保存文件。