void CloseLCD(object sender, EventArgs e)
         {
             SendMessage(this.Handle, WM_SYSCOMMAND, SC_MONITORPOWER, 2);    // 2 为关闭显示器， －1则打开显示器
         }
        SendMessage#region SendMessage
        public const uint WM_SYSCOMMAND = 0x0112;
        public const uint SC_MONITORPOWER = 0xF170;
        [DllImport("user32")]
        public static extern IntPtr SendMessage(IntPtr hWnd, uint wMsg, uint wParam, int lParam);
        #endregion

------解决方案--------------------
找找相应的API。

------解决方案--------------------

Eject USB disks using C#http://www.codeproject.com/KB/system/usbeject.aspx