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
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];
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();
}

//———————————————————-

publicvoid DownloadFile( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FileBody )
{

　　WebForm.Response.ClearHeaders();
　　WebForm.Response.Clear();
　　WebForm.Response.Expires =0;
　　WebForm.Response.Buffer =true;
　　WebForm.Response.AddHeader(“Accept-Language“, “zh-tw“);
　　//\’文件名称
　　WebForm.Response.AddHeader(“content-disposition“, “attachment; filename=\’“+System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8)+“\’“);
　　WebForm.Response.ContentType =“Application/octet-stream“;
　　//\’文件内容
　　WebForm.Response.Write(FileBody);//———–
WebForm.Response.End();
}

//上面这段代码是下载一个动态产生的文本文件，若这个文件已经存在于服务器端的实体路径，则可以通过下面的函数：

publicvoid DownloadFileByFilePath( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FilePath )
{
　　WebForm.Response.ClearHeaders();
　　WebForm.Response.Clear();
　　WebForm.Response.Expires =0;
WebForm.Response.Buffer =true;
　　WebForm.Response.AddHeader(“Accept-Language“, “zh-tw“);
　　//文件名称
　　WebForm.Response.AddHeader(“content-disposition“, “attachment; filename=\’“+ System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) +“\’“ );
　　WebForm.Response.ContentType =“Application/octet-stream“;
　　//文件内容
　　WebForm.Response.Write(System.IO.File.Rea}dAllBytes(FilePath));//———
　　WebForm.Response.End();

｝