class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            SingleInstanceApp a = new SingleInstanceApp();
            a.Run(args);
        }
    }

    /// <summary>
    /// App.xaml 的交互逻辑
    /// </summary>
    public partial class App : System.Windows.Application
    {
        protected override void OnStartup(System.Windows.StartupEventArgs e)
        {
            base.OnStartup(e);
            InitializeComponent();
        }
    }

    public class SingleInstanceApp : WindowsFormsApplicationBase
    {
        App win = null;
        public SingleInstanceApp()
        {
            this.IsSingleInstance = true;
        }

        protected override bool OnStartup(Microsoft.VisualBasic.ApplicationServices.StartupEventArgs eventArgs)
        {
            win = new App();
            win.Run();
            return false;
        }

        protected override void OnStartupNextInstance(StartupNextInstanceEventArgs eventArgs)
        {
            foreach (System.Windows.Window _win in win.Windows)
            {
                if (_win.Visibility == System.Windows.Visibility.Visible)
                {
                    _win.Activate();
                }
            }
        }
    }