protected void btnLogin_Click(object sender, EventArgs e)
        {
            User user = new User();

            user.UserName = txtUserId.Text;
            user.Password = txtPassword.Text;

            if (!user.UserLogin())
            {
                Response.Write("alert('Invalid Credentials');");
            }
            else
            {
                Session["UserName"] = user.UserName;
                int userType = user.UserType();
                switch (userType)
                {
                case 1:
                    Session["UserType"] = "Admin";

                    break;

                case 2:
                    Session["UserType"] = "Librarian";
                    break;

                case 3:
                    Session["UserType"] = "Member";
                    break;

                default:
                    Response.Write("alert('Invalid User Authentication.Please Contact Administrator')");
                    break;
                }
                Response.Redirect("~/HomePage.aspx");
            }
        }