asp.net实现文件下载功能!

Question

因要做一个自动更新功能，比如打开以下这个网址"http://www.mycom.com/update/ 
就可以获得这个升级文件的地址,实现文件下载。这个功能用asp.net是如何实现的，谢谢。

Answer 1

这就是IO文件流的操作了，你用io 判断网站的文件夹的文件是否存在 如果存在就跳转到连接文件地址 我写个简单的string filename=Server.Mapth("~/upload")+"\\"+"更新文件.zip";              if (File.Exists(filename))
                {
                    Response.Redirect(filename);
                }
这样就行了撒

Answer 2

 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();
        }

Answer 3

哪如果有几个文件呢？
这是我的代码：
protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add(new DataColumn("Name", typeof(string)));
        string serverPath = Server.MapPath("File");
        DirectoryInfo dir = new DirectoryInfo(serverPath);
        foreach (FileInfo fileName in dir.GetFiles())
        {
            DataRow dr = dt.NewRow();
            dr[0] = fileName;
            dt.Rows.Add(dr);
        }
        ListBox1.DataSource = dt;
        ListBox1.DataTextField = "Name";
        ListBox1.DataValueField = "Name";
        ListBox1.DataBind();
    }
}
protected void ListBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    Session["txt"] = ListBox1.SelectedValue.ToString();
}
protected void LinkButton1_Click(object sender, EventArgs e)
{
    if (Session["txt"] != "")
    {
        string path = Server.MapPath("File/") + Session["txt"].ToString();
        FileInfo fi = new FileInfo(path);
        if (fi.Exists)
        {
            Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode( fi.Name));
            Response.WriteFile(fi.FullName);
        }
    }

Answer 4

Refer:
http://www.cnblogs.com/insus/articles/2003336.html

Answer 5

其实我要做的是在局域网内，输入这个网址："http://www.mycom.com/update/
就可以访问里面的几个升级文件，这个功能是怎么实现 的？