Asp.net 中文件的下载

    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=z.zip");   
        string filename = Server.MapPath("DownLoad/z.zip");   
        Response.TransmitFile(filename);   
    }   
    //WriteFile实现下载    
    protected void 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();   
    }   
    //WriteFile分块下载    
    protected void 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)   
        {   
            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();   
        }   
    }   
    //流方式下载    
    protected void 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 = 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();   
    }   
//----------------------------------------------------------   

public void 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：   
public void 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.ReadAllBytes(FilePath));//---------   
WebForm.Response.End();   
}