Name of dbconnection correct. But still wrong connection...

Hello!

Just a little bug but can make a funny crash (this is all the code)
After to write my codes when "ctrl+f5" its crash and showing me this error message from the .aspx.:
The connection name 'Mfwamba' was not found in the application configuration or the connection string is empty

But the real name of my dbconnection is really 'Mfwamba'. Why this message then? Thanx.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ShowDetails.aspx.cs" Inherits="ShowDetails" %>

http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

http://www.w3.org/1999/xhtml">

   


   

////////////////////////////

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 ShowDetails : System.Web.UI.Page
{
    string strcon = "Data Source=localhost\\sqlexpress;Integrated Security=true;Initial Catalog=Mfwamba";
    SqlConnection con;
    SqlCommand cmd;
    protected void Page_Load(object sender, EventArgs e)
    {
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        con = new SqlConnection(strcon);
        con.Open();
        cmd = new SqlCommand("Select * from Emp where Empid=@id", con);
        cmd.Parameters.AddWithValue("@id", DropDownList1.Text);
        SqlDataReader dr = cmd.ExecuteReader();
        dr.Read();
        if (dr.HasRows)
        {
            Label1.Text = dr[1].ToString();
            Label2.Text = dr[2].ToString();
            Image1.ImageUrl = "~/Handler.ashx?id=" + DropDownList1.Text;
        }
        con.Close();
    }
}