downloading file is not working

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ASP.NET

Actually whenever the submit the decrpt code then file was downloaded.it is theme.

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public partial class downloadfile : System.Web.UI.Page
{
    string Id;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["fuzzyconnection"]);
            con.Open();
            Id = (string)Session["filenam"];
            SqlCommand cmd = new SqlCommand("select * from ownerfiles where filenam = '" + Id + "'", con);
            //cmd.Parameters.Add("@FileId",SqlDbType.Int).Value=1;
            DataTable dt = GetData(cmd);
            if (dt != null)
            {
                download(dt);
            }


            
            
            
        }
    }
    private DataTable GetData(SqlCommand cmd)
    {

        DataTable dt = new DataTable();
        SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["fuzzyconnection"]);
        SqlDataAdapter sda = new SqlDataAdapter();
        cmd.CommandType = CommandType.Text;
        cmd.Connection = con;
        try
        {
            con.Open();
            sda.SelectCommand = cmd;
            sda.Fill(dt);
            return dt;
        }
        catch
        {
            return null;
        }

        finally
        {
            con.Close();
            sda.Dispose();
            con.Dispose();
        }
    }
    private void download(DataTable dt)
    {
        if (dt.Rows.Count > 0)
        {
            Byte[] bytes = (Byte[])dt.Rows[0]["files"];
            Response.Buffer = true;
            Response.Charset = "";
            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            //Response.ContentType = dt.Rows[0]["Ftype"].ToString();
            Response.AddHeader("content-disposition", "attachment;filename=" + dt.Rows[0]["filenam"].ToString());
            //Response.BinaryWrite("<script type='text/javascript'> <embed src='bytes' style=width:300px; height:200px;> </embed> </script> ");
            Response.ContentType = "application/msword";
            Response.BinaryWrite(bytes);
            Response.Flush();
            Response.End();
        }
    } 




}

in this one string read null value and dt not return values.it's empty.

that's why file was not downloading.
string is like as

Id = (string)Session["filenam"];

dt like as

DataTable dt = GetData(cmd);

my problem is file was not downloading

please help me.

thank u.