C#的四种下载文件方法

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();

}
}

转载于:https://www.cnblogs.com/codeloves/archive/2013/02/17/2914054.html