private void menuItem_AccountSetting_Click(object sender, RoutedEventArgs e) { var win = new AccountSettingWindow(false); win.AccountUpdated += (account, clinet) => { MessageBox.Show( "新しいアカウント設定は次回起動から有効になります。", "LineTrader", MessageBoxButton.OK, MessageBoxImage.Information, MessageBoxResult.None, MessageBoxOptions.DefaultDesktopOnly ); }; win.ShowDialog(); }