WPF只允许创建一个应用实例代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApp5
{
     class App : Application
     {
         Mutex mutex;
         protected override void OnStartup(StartupEventArgs e)
         {
             string mutexName = "myApp";
             bool createNew;
             mutex = new Mutex(true, mutexName, out createNew);
             if (!createNew)
             {
                 MessageBox.Show("应用已经存在一个进程实例!");
                 this.Shutdown();
             }
             else
             {
                 base.OnStartup(e);
             }
         }
     }
     class Program
     {
         [STAThread]
         public static void Main(string[] args)
         {
             Application app = new App();
             Window1 window1 = new Window1();
             window1.Show();
             //app.Run();
             //下面的代码等同于上面的
             Application.Current.Run();
         }
     }
}