WPF程序，运行时，结束时，要运行的操作（自动保存，检查单程序）

 /// <summary>
    /// App.xaml 的交互逻辑
    /// </summary>
    public partial class App : Application
    {
        private void AppExit(object sender, ExitEventArgs e)
        {
            if (Context.Me != null)
            {
                Context.Me.State = 3;
                Context.PicaClient.UpdateUser(Context.Me);
            }
        }

        private void AppStartup(object sender, StartupEventArgs e)
        {
            Process[] List = Process.GetProcesses();
            if (Process.GetProcessesByName("pica2").Length > 1)
            {
                MessageBox.Show("程序已经登录，不能再次登录。");
                Application.Current.Shutdown();
            }
        }
    }