.net下载文件的常用方法汇总

1. //TransmitFile实现下载 
2.          protected void Button1_Click1(object sender, EventArgs e) 
3.         { 
4.             /* 
5.              微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite 
6.              下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。 
7.              代码如下： 
8.              */ 
9.             string strFileName = "三部闲置设备管理系统操作手册IEMS.ppt"; 
10.             Response.ContentType = "application/x-zip-compressed"; 
11.             //Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312"); 
12.             string filename = BLL.Config.PART_EM_UPLOAD_DOC + strFileName;  
13.             //BLL.Config.PART_EM_UPLOAD_DOC 为路径   ("D:/EMUploadDoc/") 
14.             Response.AddHeader("Content-Disposition", "attachment;filename=" +Server.UrlPathEncode(strFileName)); 
15.            //Server.UrlPathEncode()解决文件名的乱码问题. 
16.              
17.             Response.TransmitFile(filename); 
18.         }    //WriteFile实现下载 
19.     protected void Button2_Click(object sender, EventArgs e) 
20.     { 
21.         /* 
22.          using System.IO; 
23.           
24.          */ 
25.         string fileName = "asd.txt";//客户端保存的文件名 
26.         string filePath = Server.MapPath("DownLoad/aaa.txt");//路径 
27.         FileInfo fileInfo = new FileInfo(filePath); 
28.         Response.Clear(); 
29.         Response.ClearContent(); 
30.         Response.ClearHeaders(); 
31.         Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName); 
32.         Response.AddHeader("Content-Length", fileInfo.Length.ToString()); 
33.         Response.AddHeader("Content-Transfer-Encoding", "binary"); 
34.         Response.ContentType = "application/octet-stream"; 
35.         Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312"); 
36.         Response.WriteFile(fileInfo.FullName); 
37.         Response.Flush(); 
38.         Response.End(); 
39.     } 
40.     //WriteFile分块下载 
41.     protected void Button3_Click(object sender, EventArgs e) 
42.     { 
43.         string fileName = "aaa.txt";//客户端保存的文件名 
44.         string filePath = Server.MapPath("DownLoad/aaa.txt");//路径 
45.         System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath); 
46.         if (fileInfo.Exists == true) 
47.         { 
48.             const long ChunkSize = 102400;//100K 每次读取文件，只读取100Ｋ，这样可以缓解服务器的压力 
49.             byte buffer = new byte[ChunkSize]; 
50.             Response.Clear(); 
51.             System.IO.FileStream iStream = System.IO.File.OpenRead(filePath); 
52.             long dataLengthToRead = iStream.Length;//获取下载的文件总大小 
53.             Response.ContentType = "application/octet-stream"; 
54.             Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName)); 
55.             while (dataLengthToRead > 0 && Response.IsClientConnected) 
56.             { 
57.                 int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小 
58.                 Response.OutputStream.Write(buffer, 0, lengthRead); 
59.                 Response.Flush(); 
60.                 dataLengthToRead = dataLengthToRead - lengthRead; 
61.             } 
62.             Response.Close(); 
63.         } 
64.     } 
65.     //流方式下载 
66.     protected void Button4_Click(object sender, EventArgs e) 
67.     { 
68.         string fileName = "aaa.txt";//客户端保存的文件名 
69.         string filePath = Server.MapPath("DownLoad/aaa.txt");//路径 
70.         //以字符流的形式下载文件 
71.         FileStream fs = new FileStream(filePath, FileMode.Open); 
72.         byte bytes = new byte[(int)fs.Length]; 
73.         fs.Read(bytes, 0, bytes.Length); 
74.         fs.Close(); 
75.         Response.ContentType = "application/octet-stream"; 
76.         //通知浏览器下载文件而不是打开 
77.         Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8)); 
78.         Response.BinaryWrite(bytes); 
79.         Response.Flush(); 
80.         Response.End(); 
81.     }