C# 不管怎样，这都需要在正常模式下运行，这可能不是什么缺点。无论如何，知道有一个问题是很好的。这个方法不能被部分信任的代码使用。作为一个全球性的例子，这是一个糟糕的方法。 static Mutex mx; const strin

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不管怎样，这都需要在正常模式下运行，这可能不是什么缺点。无论如何，知道有一个问题是很好的。这个方法不能被部分信任的代码使用。作为一个全球性的例子，这是一个糟糕的方法。

        static Mutex mx;
        const string singleInstance = @"MU.Mutex";
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            try
            {
                System.Threading.Mutex.OpenExisting(singleInstance);
                MessageBox.Show("already exist instance");
                return;
            }
            catch(WaitHandleCannotBeOpenedException)
            {
                mx = new System.Threading.Mutex(true, singleInstance);

            }
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new MainForm());
        }

  string procName = Process.GetCurrentProcess().ProcessName;
  if (Process.GetProcessesByName(procName).Length == 1)
  {
      ...code here...
  }

        bool haveLock = false;
        try
        {
            lockStream = new System.IO.FileStream(pathToTempFile,System.IO.FileMode.Create,System.IO.FileAccess.ReadWrite,System.IO.FileShare.None);
            haveLock = true;
        }
        catch(Exception)
        {
            System.Console.WriteLine("Failed to acquire lock. ");
        }
        if(!haveLock)
        {
            Inka.Controls.Dialoge.InkaInfoBox diag = new Inka.Controls.Dialoge.InkaInfoBox("App has been started already");
            diag.Size = new Size(diag.Size.Width + 40, diag.Size.Height + 20);
            diag.ShowDialog();
            Application.Exit();
        }

public class SingleInstanceApplication : WindowsFormsApplicationBase
{
    private SingleInstanceApplication()
    {
        base.IsSingleInstance = true;
    }

    public static void Run(Form f, StartupNextInstanceEventHandler startupHandler)
    {
        SingleInstanceApplication app = new SingleInstanceApplication();
        app.MainForm = f;
        app.StartupNextInstance += startupHandler;
        app.Run(Environment.GetCommandLineArgs());
    }
}

using Microsoft.VisualBasic.ApplicationServices;

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        SingleInstanceApplication.Run(new Form1(), StartupNextInstanceEventHandler);
    }

    public static void StartupNextInstanceEventHandler(object sender, StartupNextInstanceEventArgs e)
    {
        MessageBox.Show("New instance");
    }
}

public partial class App : Application
{
    const string AppId = "MY APP ID FOR THE MUTEX";
    static Mutex mutex = new Mutex(false, AppId);
    static bool mutexAccessed = false;

    protected override void OnStartup(StartupEventArgs e)
    {
        try
        {
            if (mutex.WaitOne(0))
                mutexAccessed = true;
        }
        catch (AbandonedMutexException)
        {
            //handle the rare case of an abandoned mutex
            //in the case of my app this isn't a problem, and I can just continue
            mutexAccessed = true;
        }

        if (mutexAccessed)
            base.OnStartup(e);
        else
            Shutdown();
    }

    protected override void OnExit(ExitEventArgs e)
    {
        if (mutexAccessed)
            mutex?.ReleaseMutex();

        mutex?.Dispose();
        mutex = null;
        base.OnExit(e);
    }
}

 /// <summary>
        /// The main entry point for the application.
        /// Limit an app.to one instance
        /// </summary>
        [STAThread]
        static void Main()
        {
            //Mutex to make sure that your application isn't already running.
            Mutex mutex = new System.Threading.Mutex(false, "MyUniqueMutexName");
            try
            {
                if (mutex.WaitOne(0, false))
                {
                    // Run the application
                    Application.EnableVisualStyles();
                    Application.SetCompatibleTextRenderingDefault(false);
                    Application.Run(new Form1());
                }
                else
                {
                    MessageBox.Show("An instance of the application is already running.",
                        "An Application Is Running", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Application Error 'MyUniqueMutexName'", 
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            finally
            {
                if (mutex != null)
                {
                    mutex.Close();
                    mutex = null;
                }
            }
        }