static class Program
    {
      internal static  ApplicationContext  context = new ApplicationContext(new Form1());
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();            
            Application.Run(context);
        }
    }

            Form2 form = new Form2();
            Program.context.MainForm = form;
            form.Show();