static class Program

{

    private static System.Threading.Mutex mutex;

    /// <summary>

    /// 应用程序的主入口点。

    /// </summary>

    [STAThread]

    static void Main()

    {

        Application.EnableVisualStyles();

        Application.SetCompatibleTextRenderingDefault(false);

        mutex = new System.Threading.Mutex(true, "OnlyRun");

        if(mutex.WaitOne(0, false))

        {

            Application.Run(new MainForm());

        }

        else

        {

            MessageBox.Show("程序已经在运行！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

            Application.Exit();

        }

    }

}

static class Program

{

    /// <summary>

    /// 应用程序的主入口点。

    /// </summary>

    [STAThread]

    static void Main()

    {

        Application.EnableVisualStyles();

        Application.SetCompatibleTextRenderingDefault(false);

        // get the name of our process

        string p = System.Diagnostics.Process.GetCurrentProcess().ProcessName;

        // get the list of all processes by that name

        System.Diagnostics.Process[] processes = System.Diagnostics.Process.GetProcessesByName(p);

        // if there is more than one process

        if(processes.Length > 1)

        {

            MessageBox.Show("程序已经在运行中", "系统提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

            Application.Exit();

        }

        else

        {

            Application.Run(new MainForm());

        }

    }

}