C#中实现文件下载的四种方法总结

using System;  
using System.Data;  
using System.Configuration;  
using System.Web;  
using System.Web.Security;  
using System.Web.UI;  
using System.Web.UI.WebControls;  
using System.Web.UI.WebControls.WebParts;  
using System.Web.UI.HtmlControls;  
using System.IO;  
 
public partial class _Default : System.Web.UI.Page  
{  
protected void Page_Load(object sender, EventArgs e)  
{  
 
} 

//TransmitFile实现下载
 

protected void Button1_Click(object sender, EventArgs e)  
{  
 
 
Response.ContentType = "application/x-zip-compressed";  
Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");  
string filename = Server.MapPath("DownLoad/z.zip");  
Response.TransmitFile(filename);  
}  

//WriteFile实现下载
 

protected void Button2_Click(object sender, EventArgs e)  
{  
 
 
string fileName ="asd.txt";//客户端保存的文件名  
string filePath=Server.MapPath("DownLoad/aaa.txt");//路径  
 
FileInfo fileInfo = new FileInfo(filePath);  
Response.Clear();  
Response.ClearContent();  
Response.ClearHeaders();  
Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);  
Response.AddHeader("Content-Length", fileInfo.Length.ToString());  
Response.AddHeader("Content-Transfer-Encoding", "binary");  
Response.ContentType = "application/octet-stream";  
Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");  
Response.WriteFile(fileInfo.FullName);  
Response.Flush();  
Response.End();  
}  

//WriteFile分块下载
 

protected void Button3_Click(object sender, EventArgs e)  
{  
 
string fileName = "aaa.txt";//客户端保存的文件名  
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径  
 
System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);  
 
if (fileInfo.Exists == true)  
{  
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  
byte[] buffer = new byte[ChunkSize];  
 
Response.Clear();  
System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);  
long dataLengthToRead = iStream.Length;//获取下载的文件总大小  
Response.ContentType = "application/octet-stream";  
Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));  
while (dataLengthToRead > 0 && Response.IsClientConnected)  
{  
int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小  
Response.OutputStream.Write(buffer, 0, lengthRead);  
Response.Flush();  
dataLengthToRead = dataLengthToRead - lengthRead;  
}  
Response.Close();  
}  
}  

//流方式下载
 

protected void Button4_Click(object sender, EventArgs e)  
{  
string fileName = "aaa.txt";//客户端保存的文件名  
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径  
 
//以字符流的形式下载文件  
FileStream fs = new FileStream(filePath, FileMode.Open);  
byte[] bytes = new byte[(int)fs.Length];  
fs.Read(bytes, 0, bytes.Length);  
fs.Close();  
Response.ContentType = "application/octet-stream";  
//通知浏览器下载文件而不是打开  
Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));  
Response.BinaryWrite(bytes);  
Response.Flush();  
Response.End();  
 
}  
}