c#如何获知机器处于锁屏状态

Question

如题，望大虾指点。

Answer 1

http://blog.csdn.net/windless0530/article/details/5496469

Answer 2

@mjfmjf,非常感谢，思路非常重要！以下代码本地调试成功。
class SessionChangeHandler : Control // allows us to override WndProc
    {
        [DllImport("WtsApi32.dll")]
        private static extern bool WTSRegisterSessionNotification(IntPtr hWnd, [MarshalAs(UnmanagedType.U4)]int dwFlags);
        [DllImport("WtsApi32.dll")]
        private static extern bool WTSUnRegisterSessionNotification(IntPtr hWnd);        private const int NOTIFY_FOR_THIS_SESSION = 0;
        private const int WM_WTSSESSION_CHANGE = 0x2b1;
        private const int WTS_SESSION_LOCK = 0x7;
        private const int WTS_SESSION_UNLOCK = 0x8;        public SessionChangeHandler()
        {
            if (!WTSRegisterSessionNotification(this.Handle, NOTIFY_FOR_THIS_SESSION))
            {
                Marshal.ThrowExceptionForHR(Marshal.GetLastWin32Error());
            }
        }        protected override void OnHandleDestroyed(EventArgs e)
        {
            // unregister the handle before it gets destroyed
            WTSUnRegisterSessionNotification(this.Handle);
            base.OnHandleDestroyed(e);
        }        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_WTSSESSION_CHANGE)
            {
                int value = m.WParam.ToInt32();
                if (value == WTS_SESSION_LOCK)
                {
                    OnMachineLocked(EventArgs.Empty);
                }
                else if (value == WTS_SESSION_UNLOCK)
                {
                    OnMachineUnlocked(EventArgs.Empty);
                }
            }
            base.WndProc(ref m);
        }        protected virtual void OnMachineLocked(EventArgs e)
        {
            EventHandler temp = myMachineLockedHandler;
            if (temp != null)
            {
                temp(this, e);
            }
        }        protected virtual void OnMachineUnlocked(EventArgs e)
        {
            EventHandler temp = myMachineUnlockedHandler;
            if (temp != null)
            {
                temp(this, e);
            }
        }        public EventHandler myMachineLockedHandler { get; set; }        public EventHandler myMachineUnlockedHandler { get; set; }
    }以上代码摘录自http://pinvoke.net/default.aspx/wtsapi32.WTSRegisterSessionNotification