asp.net下载文件几种方式

一、//TransmitFile实现下载
protectedvoid Button1_Click(object sender, EventArgs e)
{
/*
微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite
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。
代码如下：
*/
Response.ContentType ="application/x-zip-compressed";
Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");
string filename = Server.MapPath("DownLoad/z.zip");
Response.TransmitFile(filename);
}

二、//WriteFile实现下载
protectedvoid Button2_Click(object sender, EventArgs e)
{
/*
using System.IO;

*/
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();
}

三、 //WriteFile分块下载
protectedvoid Button3_Click(object sender, EventArgs e)
{
string fileName ="aaa.txt";//客户端保存的文件名 www.2cto.com
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

System.IO.FileInfo fileInfo =new System.IO.FileInfo(filePath);

if (fileInfo.Exists ==true)
{
constlong 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 =newbyte[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();
}
}

四、//流方式下载
protectedvoid 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 =newbyte[(int)fs.Length];