private void BTNDelete_Click(object sender, EventArgs e)
        {
            CustomersForm c = new CustomersForm()
            {
                IsDailog = true
            };
            DialogResult r = c.ShowDialog();

            if (c.DialogResult == DialogResult.OK)
            {
                TXTCustomerName.Text = c.CustomerFirstName + " " + c.CustomerLastName;
                CBMobileNo.Text      = c.CustomerMobileNo;
            }
            c.Dispose();
            CKNewCustomer.Checked = true;
        }
        private void BTNNewCustomer_Click(object sender, EventArgs e)
        {
            //TODO: when MobileNo is added to text , disable  field change event
            CustomersForm c = new CustomersForm()
            {
                IsDailog = true
            };
            DialogResult r = c.ShowDialog();

            if (c.DialogResult == DialogResult.OK)
            {
                TXTFirstName.Text = c.CustomerFirstName;
                TXTLastName.Text  = c.CustomerLastName;
                CBMobileNo.Items.Add(c.CustomerMobileNo);
                CBMobileNo.Text = c.CustomerMobileNo;
            }
            c.Dispose();
        }