winForm单击用户区可移动窗体，代码控制窗体最大适中

  protected override void WndProc(ref System.Windows.Forms.Message m)//zhaosn
        {
            base.WndProc(ref m);
            if (m.Msg == 132)
            {
                if ((IntPtr)1 == m.Result)
                {
                    m.Result = (IntPtr)2;
                }
            }
        }

this.WindowState = FormWindowState.Normal;
this.WindowState = FormWindowState.Maximized;

原文：http://www.cnblogs.com/susuzhao/p/3521338.html