void btnOK_Click(object sender, EventArgs e) { if (txtShortName.Text == string.Empty || txtLongName.Text == string.Empty) { Tools.UserInfoHandler.ShowError("Please indicate a short name and a long name for the add-on."); return; } if (CountryAdministrator.DoesCountryExist(txtShortName.Text)) { Tools.UserInfoHandler.ShowError("Add-on named '" + txtShortName.Text + "' already exists."); return; } if (txtSymbol.Text != string.Empty && !CountryAdministrator.IsValidFlagFilePath(txtSymbol.Text)) { return; } if (lstAddOnSystems.CheckedItems.Count == 0 || lstBaseSystems.CheckedItems.Count == 0) { Tools.UserInfoHandler.ShowError("Please select an add-on system and a base system."); return; } _addOnSystemName = lstAddOnSystems.SelectedItem.ToString(); _baseSystemName = lstBaseSystems.SelectedItem.ToString(); if (_addOnSystemName == _baseSystemName) { Tools.UserInfoHandler.ShowError("Add-on system must be different from base system."); return; } DialogResult = DialogResult.OK; Close(); }