private void dealerButton_Click(object sender, EventArgs e) { string dealerName = nameTextBox.Text; string dealerCompanyName = cNameTextBox.Text; string contact = contactTextBox.Text; string address = addressTextBox.Text; string city = cityTextBox.Text; dealer.DealerName = nameTextBox.Text; dealer.DealerCompanyName = cNameTextBox.Text; dealer.Contact = contactTextBox.Text; dealer.Address = addressTextBox.Text; dealer.City = cityTextBox.Text; if (dealerName == "" || dealerCompanyName == "" || contact == "" || address == "" || city == "") { MessageBox.Show("Please Field must not be empty.."); return; } if (_dealerManager.Add(dealer)) { MessageBox.Show("Added"); List <Dealer> dealers = _dealerManager.Display(); showDataGridView.DataSource = dealers; return; } else { MessageBox.Show("Not Added"); } }