/// <summary>App.xaml 的交互逻辑</summary>
    public partial class App : Application
    {
        private bool bFirst = true;
        private User user;

        protected override void OnStartup(StartupEventArgs e)
        {
            if (bFirst)
            {
                Application.Current.ShutdownMode = System.Windows.ShutdownMode.OnExplicitShutdown;
                WndLogin window = new WndLogin();
                bool? dialogResult = window.ShowDialog();

                if ((dialogResult.HasValue) && (dialogResult.Value))
                {
                    user = window.CurrentUser;
                    bFirst = false;

                    OnStartup(e);
                    Application.Current.ShutdownMode = ShutdownMode.OnLastWindowClose;
                }
                else
                {
                    Shutdown();
                }
            }
            else
            {
                MainWindow window = new MainWindow();
                window.curUser = user;
                window.ShowDialog();
            }
        }
    }