//下载的四种方法
protected void Button1_Click(object sender, EventArgs e)
{
//TransmitFile实现下载
/**/
/*
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=keji.rar");
string filename = Server.MapPath("keji.rar");
Response.TransmitFile(filename);
Response.Write("<script language=\"javascript\" type=\"text/javascript\">");
Response.Write("alert(\"下载成功\");");
Response.Write("window.location.href=\"C_SC.aspx\";");
Response.Write("</script>");
}protected void Button2_Click(object sender, EventArgs e)
{//WriteFile实现下载
string fileName = "ceshi.rar";//客户端保存的文件名
string filePath = Server.MapPath("keji.rar");//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();
}protected void Button3_Click(object sender, EventArgs e)
{
//WriteFile分块下载
string fileName = "GhostXP.iso";//客户端保存的文件名
string filePath = Server.MapPath("GhostXP7.7.iso");//路径
System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);if (fileInfo.Exists == true)
{
const long ChunkSize = 409600;//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();
}
}//字符流方式下载文件
protected void Button4_Click(object sender, EventArgs e)
{
string fileName = "ce2.rar";//客户端保存的文件名
string filePath = Server.MapPath("keji.rar");//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();
} 
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