ASP.NET page with a C# code-behind is not working when trying to download a file

Hi this is the current version......please help.

<%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="FormDownload.aspx.cs" Inherits="Default2" Title="Form Download" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="LoginContent" Runat="Server">
</asp:Content>
<asp:Content ID="Content3" ContentPlaceHolderID="MainContent" Runat="Server">
 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" CellPadding="2"
                ForeColor="#333333" GridLines="None" AllowPaging="True" 
        onselectedindexchanged="GridView1_SelectedIndexChanged" CellSpacing="10" 
        HorizontalAlign="Center">
                <Columns>
                    <asp:TemplateField>
                        <ItemTemplate>
                            <asp:LinkButton ID="lnkdownload" runat="server" Text="Download" CommandName="Download"
                                CommandArgument='<%#Eval("FullName") +";" + Eval("Name") %>'></asp:LinkButton>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:BoundField DataField="Name" HeaderText="File Name" />
                    <asp:BoundField DataField="Length" HeaderText="Size (Bytes)" />
                </Columns>
                <FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
                <RowStyle BackColor="#E3EAEB" />
                <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
                <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
                <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
                <EditRowStyle BackColor="#7C6F57" />
                <AlternatingRowStyle BackColor="White" />
            </asp:GridView>
</asp:Content>

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;

public partial class Default2 : System.Web.UI.Page
{
    private void BindGrid()
    {
        DirectoryInfo dir = new DirectoryInfo(&quo开发者_运维知识库t;D:/Pilabs Projects/GlobeDse/globedse website/globedse.com/Uploads");
        FileInfo[] files = dir.GetFiles();
        GridView1.DataSource = files;
        GridView1.DataBind();


    }

    protected void Page_Load(object sender, EventArgs e)
    {


        if (!Page.IsPostBack)
        {
             BindGrid();
        }
       



    }

    private void Downloadfile(String fileName, String FullFilePath)
    {
 
        Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);
        Response.TransmitFile(FullFilePath);
        Response.End();


    }

    protected void GridView1_RowCommand(object sender, System.Web.UI.WebControls.GridViewCommandEventArgs e)
    {
        if (e.CommandName == "Download")
        {
            String[] fileInfo = e.CommandArgument.ToString().Split(';');
            String FileName = fileInfo[1].ToString();
            String FullPath = fileInfo[0].ToString();
            Downloadfile(FileName, FullPath);
        }

    }


    protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {

        GridView1.PageIndex = e.NewPageIndex
        BindGrid();


    }
}

First, check if your method Downloadfile is getting hit. You also did

Response.Write(FullPath);

which kinda ruins your output. I'd rather design it that you redirect to another page which outputs the download.

You're missing a check for postbacks. Your Page_Load should look something like this:

protected void Page_Load(object sender, EventArgs e) 
{ 
  if (!Page.IsPostBack)
  {
    BindGrid();
  }
}

When you re-databind the grid, the events are lost.