protected void CustomerDeleteButton_Click(object sender, EventArgs e)
    {
        clsCustomerCollection Customers = new clsCustomerCollection();

        if (CustomerListBox.SelectedIndex != -1)
        {
            int Id = Convert.ToInt32(CustomerListBox.SelectedValue);
            Customers.thisCustomer.Find(Id);
            clsCustomer selectedCustomer = Customers.thisCustomer;
            Customers.delete();
        }
        else
        {
            ErrorLabel.Text = "[!] A record must be selected";
        }
    }