protected void btnLogin_Click(object sender, EventArgs e) { //create an instance of the authentication class clsLogin Login = new clsLogin(); //declare a variable to store the customer no if the user who logged in Int32 CustomerNo; //authenticate the login CustomerNo = Login.SignIn(txtUserName.Text, txtPassword.Text); //if there is a customer number returned if (CustomerNo != 0) { //set the CustomerNumber Booking.CustomerNo = CustomerNo; //go onto the next step Response.Redirect("Checkout.aspx"); } else { //otherwise the login failed so report an error lblError.Text = "Login failed"; } }