WPF-禁止二次启动

App.xaml.cs

        protected override void OnStartup(StartupEventArgs e)
        {
            //禁止二次启动
            this.Startup += new StartupEventHandler(App_Startup);
            base.OnStartup(e);
        }
        #region 禁止二次启动
        // 用于激活已打开的窗体
        [DllImport("user32.dll")]
        public static extern void SetForegroundWindow(IntPtr hwnd);
        //操作当前窗体
        //nCmdShow: 0关闭窗口/1正常大小显示窗口/2最小化窗口/3最大化窗口
        [DllImport("user32.dll")]
        public static extern int ShowWindow(IntPtr hwnd, int nCmdShow);

        System.Threading.Mutex mutex;
        void App_Startup(object sender, StartupEventArgs e)
        {
            bool ret;
            mutex = new System.Threading.Mutex(true, "WpfDemo", out ret);
            if (!ret)
            {
                System.Diagnostics.Process[] proc = System.Diagnostics.Process.GetProcessesByName("WpfDemo");
                foreach (System.Diagnostics.Process p in proc)
                {
                    SetForegroundWindow(p.MainWindowHandle);
                    ShowWindow(p.MainWindowHandle, 1);
                    NoSecond.SendMessage(p.MainWindowHandle);
                }
                Environment.Exit(0);
            }
        }
        #endregion

NoSecond.cs

    /// <summary>
    /// 禁止程序二次启动
    /// </summary>
    public class WPFNoSecond
    {
        public const int NoSecond_DATA = 0x004A;
        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage
        (
                IntPtr hWnd,                   //目标窗体句柄
                int Msg,                       //WM_COPYDATA
                int wParam,                                             //自定义数值
                ref  CopyDataStruct lParam             //结构体
        );
        [StructLayout(LayoutKind.Sequential)]
        public struct CopyDataStruct
        {
            public IntPtr dwData;
            public int cbData;//字符串长度
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;//字符串
        }

        public static void SendMessage(IntPtr thisIntPtr)
        {
            IntPtr xmlIntPt = new IntPtr(GetIntPtr());
            if (xmlIntPt != IntPtr.Zero || thisIntPtr != IntPtr.Zero)
            {
                CopyDataStruct cds;
                cds.dwData = IntPtr.Zero;
                cds.lpData = "0123";
                cds.cbData = 4;//注意：长度为字节数
                int fromWindowHandler = 0;// 消息来源窗体
                SendMessage(thisIntPtr.ToInt32() == 0 ? xmlIntPt : thisIntPtr, NoSecond_DATA, fromWindowHandler, ref  cds);
            }
        }

        #region 窗体句柄指针
        static string _IntPtrDataDic = AppDomain.CurrentDomain.BaseDirectory + "/XML/";
        static string _IntPtrDataName = "Data.xml";
        static void intPtrDataExists()
        {
            try
            {
                if (!System.IO.File.Exists(_IntPtrDataDic))
                {
                    if (!Directory.Exists(_IntPtrDataDic)) { Directory.CreateDirectory(_IntPtrDataDic); }
                    XmlDocument doc = new XmlDocument();
                    doc.AppendChild(doc.CreateXmlDeclaration("1.0", "utf-8", ""));
                    XmlElement root = doc.CreateElement("Root");
                    root.InnerText = "0";
                    doc.AppendChild(root);
                    doc.Save(_IntPtrDataDic);
                }
            }
            catch (Exception) { }
        }
        static int GetIntPtr()
        {
            intPtrDataExists();
            XDocument xml = XDocument.Load(_IntPtrDataDic + _IntPtrDataName);
            XElement xmlRoot = xml.Root;
            return Convert.ToInt32(xmlRoot.Value);
        }
        public static void SetIntPtr(string intPtr)
        {
            intPtrDataExists();
            XDocument xml = XDocument.Load(_IntPtrDataDic + _IntPtrDataName);
            XElement xmlRoot = xml.Root;
            xmlRoot.Value = intPtr;
            xml.Save(_IntPtrDataDic + _IntPtrDataName);
        }
        #endregion
    }

Window.cs

        #region 禁止二次启动
        private void Window_SourceInitialized(object sender, EventArgs e)
        {
            HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
            if (source == null) { throw new Exception("Cannot get HwndSource instance."); }
            source.AddHook(new HwndSourceHook(this.WndProc));
        }
        private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        {
            try
            {
                switch (msg)
                {
                    case WPFNoSecond.NoSecond_DATA:
                        this.Show();
                        break;
                }
            }
            catch (Exception) { }
            return IntPtr.Zero;
        }
        #endregion
        //最小化到托盘
        private void Window_Min(object sender, RoutedEventArgs e)
        {
            //存储当前窗体句柄
            WPFNoSecond.SetIntPtr(new WindowInteropHelper(this).Handle.ToString());
        }