Label lblwelcome = this.Master.FindControl("lblwelcome") as Label;
        Label lbluser = this.Master.FindControl("lbluser") as Label;
        LinkButton lnklogin = this.Master.FindControl("lnklogin") as LinkButton;
        Session["Username"] = txtUserName.Text;
        Session["Department"] = dt.Rows[0]["DEPERTMENT"].ToString();
        Session["loginStatus"] = "LogOut";
        Response.Redirect("~/Default.aspx");

    }
    else
    {
        FailureText.Text = "Invalid Username and Password";
    }