今天总结了下下载的几种方法。把代码贴出来了，方便自己以后查找。
下载的4种方式：
1、TransmitFile实现下载
[code lang="csharp"]
private void DownLoadByTransmitFile(string filePath,string filename)
{
/*
* 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。
*/
Response.ContentType = "application/x-zip-compressed";
Response.AddHeader("Content-Disposition",string.Format("attachment;filename={0}",filename));
Response.TransmitFile(filePath);
}
[/code]
2、WriteFile实现下载
[code lang="csharp"]
private void DownLoadByWriteFile(string filePath, string fileName)
{
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();
}
[/code]
3、WriteFile分块下载
[code lang="csharp"]
private void DownLoadByWriteFilePart(string filePath, string fileName)
{
FileInfo fileInfo = new 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();
FileStream iStream = File.OpenRead(filePath);
long dataLengthToRead = iStream.Length;//获取下载文件总大小
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();
}
}
[/code]
4、字符流形式下载
[code lang="csharp"]
private void DownLoadByIO(string filePath, string fileName)
{
//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();
}
[/code]
下载的方法：
[code lang="csharp"]
//下载
protected void Button1_Click(object sender, EventArgs e)
{
string filename="11.txt";
string filePath = Server.MapPath(filename);
DownLoadByTransmitFile(filePath, filename);
}
[/code]