文件下载代码

 

using System.IO;

 

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack) //首次加载
        {
            string[] AllTxt = Directory.GetFiles(Server.MapPath("File"));
            foreach (string name in AllTxt)
            {
                //将文件名添加到ListBox中
                ListBox1.Items.Add(Path.GetFileName(name));
            }
        }
    }

    protected void ListBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        Session["select"] = ListBox1.SelectedValue.ToString();
    }

    protected void DownButton1_Click(object sender, ImageClickEventArgs e)
    {
        //判断是否选择文件名
        if (ListBox1.SelectedValue != "")
        {
            if (Session["select"] != "")
            {   //获取文件路径
                string FilePath = Server.MapPath("File/") + Session["select"].ToString();
                //初始化 FileInfo 类的实例，它作为文件路径的包装
                FileInfo Filepath = new FileInfo(FilePath);

                //判断文件是否存在
                if (Filepath.Exists)
                {
                    //将文件保存到本机上
                    Response.Clear();
                    Response.AddHeader("Content-Disposition", "attachment; filename=" + Server.UrlEncode(Filepath.Name));
                    Response.AddHeader("Content-Length", Filepath.Length.ToString());
                    Response.ContentType = "application/octet-stream";
                    Response.Filter.Close();
                    Response.WriteFile(Filepath.FullName);
                    Response.End();
                }
            }
        }
        else
        {
            Page.RegisterStartupScript("sb", "<script>alert('请先选择文件名')</script>");
        }
    }