asp.net 下载附件功能的实现

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Web;
 5 using System.Web.UI;
 6 using System.Web.UI.WebControls;
 7 using System.Data.SqlClient;
 8 using System.Data;
 9 using System.IO;
10 using System.Text;
11 public partial class CommonPage_File_Mg_Details : System.Web.UI.Page
12 {
13     protected string ReverseString(string s)
14     {
15         char[] chars = s.ToCharArray();
16         Array.Reverse(chars);
17         return new string(chars);
18     }
19     string downLink = ""; 
20     protected void Page_Load(object sender, EventArgs e)
21     {
22         //string Indicator="url=";
23         string url = Request.Url.ToString();
24         //int index = url.IndexOf(Indicator);
25         //string urlpar = url.Substring(index + Indicator.Length, url.Length - index - Indicator.Length);
26         string s = "";
27         for (int i = url.Length - 1; i >= 0; i--)
28         {
29             if (url[i] == '=') break;
30             s += url[i];
31         }
32         s = ReverseString(s); 
33         OpreationDB db = new OpreationDB();
34 
35         string sqlStr = "select *  from [File] where No ="+s;
36         SqlDataReader dr = db.ExceRead(sqlStr);
37         if (dr.Read())
38         {
39             //tb1.Text = dr[0].ToString().Trim();
40             tb1.Text = dr["Fcontent"].ToString().Trim();
41             downLink = dr["Flink"].ToString();//下载链接
42         }
43     }
44     protected void btn_down_Click(object sender, EventArgs e)
45     {
46         string strFileName ="";
47         int j;
48         for (j = downLink.Length - 1; j >= 0; j--)
49         {
50             if(downLink[j]=='/')break;
51             strFileName += downLink[j];
52         }
53         strFileName = ReverseString(strFileName);
54 
55         string strpath = Server.MapPath("~/" + "App_Data") + "/" + strFileName;
56         FileInfo fi = new FileInfo(strpath);
57         Response.Clear();
58         Response.ClearHeaders();
59         Response.Buffer = true;
60         Response.ContentType = "application/octet-stream";
61         Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fi.Name));
62         Response.AppendHeader("Content-Length", fi.Length.ToString());
63         Response.WriteFile(fi.FullName);
64         Response.Flush();
65         Response.End();
66         
67     }
68 }

其中 Request.Url.ToString();用来获得页面的路径，配合字符串截取，能得到参数No，通过SQL语句查询File表中的上传附件的链接。然后套用下载附件的代码，实现点击下载功能。

未避免文件名字相同可以把时间戳加到文件名字中.

posted on 2016-07-05 10:35 Beserious 阅读(280) 评论(0) 编辑收藏举报