c#学习笔记 只运行一个实例

static class Program
    {
         public static MainForm mainForm;
       /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            bool initiallyOwned = true;
            bool isCreated;
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            Mutex m = new Mutex(initiallyOwned, "14E260D2-A7E8-43b8-9ECD-2A426FAA79B9", out isCreated);
            if (!(initiallyOwned && isCreated))
            {
                MessageBox.Show("软件已经在运行中!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                Application.Exit();
            }
            else
            {
                

                Application.Run(new mainForm());
            }
            
        }
    }