WinForm 窗体中实现单例模式

方式一: 单进程的实现

   static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            
            //获取当前进程名称
            string currentProcessName = Process.GetCurrentProcess().ProcessName;

            //把该名称的所有进程的列表
            Process[] process = Process.GetProcessesByName(currentProcessName);

            if (process.Length > 1)
            {
                MessageBox.Show("程序已经运行");
                return;
            }
            Application.Run(new ThMain());
        }
    }

方式二:窗体单例模式的实现

 public static Form1 thMian = null;

 /// <summary>
        /// 获取单个实例
        /// </summary>
        /// <returns></returns>
        public static Form1 GetInstance()
        {
            if (thMian == null || thMian.IsDisposed == true)  //newForm.IsDisposed == true必需，否则会出现“访问已释放资源”的异常
            {
                thMian = new Form1();
            }
            else
            {
                thMian.Activate();
            }
            return thMian;
        }

调用:
  GetInstance();
  thMian.Show();