方式一:TransmitFile实现下载。将指定的文件直接写入 HTTP 响应输出流,而不在内存中缓冲该文件。
protected
void 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=CodeShark.zip");
string filename
= Server.MapPath("DownLoad/CodeShark.zip");
Response.TransmitFile(filename);
}
方式二:WriteFile实现下载,将指定的文件直接写入 HTTP 响应输出流。注意:对大型文件使用此方法时,调用此方法可能导致异常。可以使用此方法的文件大小取决于 Web 服务器的硬件配置。
protected
void Button2_Click(object sender, EventArgs e)

...{
string fileName
= "CodeShark.zip";//客户端保存的文件名
string filePath
= Server.MapPath("DownLoad/CodeShark.doc");//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();
}
方式三:WriteFile分块下载
protected
void Button3_Click(object sender, EventArgs e)

...{
string fileName
= "CodeShark.zip";//客户端保存的文件名
string filePath
= Server.MapPath("DownLoad/CodeShark.zip");//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();
}
}
方式四:流方式下载
protected
void Button4_Click(object sender, EventArgs e)

...{
string fileName
= "CodeShark.zip";//客户端保存的文件名
string filePath
= Server.MapPath("DownLoad/CodeShark.zip");//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();
}