protected void btn_register(object sender, EventArgs e)
        {
            string admin = sr.AddAdmin(sr.GetUser(Convert.ToInt32(UserId.Value)), Surname.Value);

            if (admin == "added")
            {
                Response.Redirect("Login.aspx");
            }
            else if (admin == "Something went wrong try again")
            {
                error.Text    = "Something went wrong, please try again later";
                error.Visible = true;
            }
            else if (admin == "unsuccessful")
            {
                error.Text = "The admin already exists";
            }
        }