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, );
                     NoSecond.SendMessage(p.MainWindowHandle);
                 }
                 Environment.Exit();
             }
         }
         #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 = "";
                 cds.cbData = ;//注意：长度为字节数
                 int fromWindowHandler = ;// 消息来源窗体
                 SendMessage(thisIntPtr.ToInt32() ==  ? 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 = "";
                     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());
         }