http://stackoverflow.com/questions/184084/how-to-force-c-sharp-net-app-to-run-only-one-instance-in-windows

using System.Threading;[DllImport("user32.dll")][return: MarshalAs(UnmanagedType.Bool)]static extern bool SetForegroundWindow(IntPtr hWnd);/// <summary>/// The main entry point for the application./// </summary>[STAThread]static void Main(){   bool createdNew = true;   using (Mutex mutex = new Mutex(true, "MyApplicationName", out createdNew))   {      if (createdNew)      {         Application.EnableVisualStyles();         Application.SetCompatibleTextRenderingDefault(false);         Application.Run(new MainForm());      }      else      {         Process current = Process.GetCurrentProcess();         foreach (Process process in Process.GetProcessesByName(current.ProcessName))         {            if (process.Id != current.Id)            {               SetForegroundWindow(process.MainWindowHandle);               break;            }         }      }   }}

上面代码的MyApplicationName需要确保是唯一识别的，使用Process.GetCurrentProcess().MainModule.FileName提示说找不到文件

http://stackoverflow.com/questions/4313756/creating-a-mutex-throws-a-directorynotfoundexception

My mutex name had \ in it, which windows was interpreting as a path character. Running:

将路径名中的反斜杠替换成_就可以了

坑爹的是又出现新问题

问题1：

bool createdNew;
string appName;
appName = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name;
appName = @"Local\" + appName;    //Local\ZITaker
using (Mutex mutex = new Mutex(true, appName, out createdNew))

此段代码的问题在于，两个程序的Assembly.GetExecutingAssembly().GetName().Name会是一致的

问题2：

bool createdNew;
string appName;
appName = Process.GetCurrentProcess().MainModule.FileName;
appName = @"Local\" + appName;
using (Mutex mutex = new Mutex(true, appName, out createdNew))

这个会提示未能找到路径

正确的做法：

string appName;
appName = Process.GetCurrentProcess().MainModule.FileName;
appName = appName.Replace(Path.DirectorySeparatorChar, ‘_‘);
using (Mutex mutex = new Mutex(true, appName, out createdNew))

如何确保C#的应用程序只被打开一次