捕获 ActiveSyncEnd 事件：答案

【问题标题】：Trapping ActiveSyncEnd event:捕获 ActiveSyncEnd 事件：
【发布时间】：2010-12-06 17:54:57
【问题描述】：

我正在编写一个应用程序（PocketPc 2003 上的 .NET Compact Framework 3.5）我正在尝试检测已检测到但非常不稳定的摇篮事件。例如，在每次检测时，while 循环都会运行两次。这是因为 ActiveSyncEnd 事件的多次注册吗？我该如何纠正这个问题？

    ///NOTIFICATION_EVENT_NONE                =  0,
    ///NOTIFICATION_EVENT_TIME_CHANGE         =  1,
    ///NOTIFICATION_EVENT_SYNC_END            =  2,
    ///NOTIFICATION_EVENT_ON_AC_POWER         =  3,
    ///NOTIFICATION_EVENT_OFF_AC_POWER        =  4,
    ///NOTIFICATION_EVENT_NET_CONNECT         =  5,
    ///NOTIFICATION_EVENT_NET_DISCONNECT      =  6,
    ///NOTIFICATION_EVENT_DEVICE_CHANGE       =  7,
    ///NOTIFICATION_EVENT_IR_DISCOVERED       =  8,
    ///NOTIFICATION_EVENT_RS232_DETECTED      =  9,
    ///NOTIFICATION_EVENT_RESTORE_END         = 10,
    ///NOTIFICATION_EVENT_WAKEUP              = 11,
    ///NOTIFICATION_EVENT_TZ_CHANGE           = 12,
    ///NOTIFICATION_EVENT_MACHINE_NAME_CHANGE = 13      

// In DeviceEventManager       
public void ActiveSyncEndDetect()
{
    try
    {
        // Put 9 for cradle event, 2 for ActiveSyncEnd event, 0 for none. 
        handleActiveSyncEndEvent = NativeMethods.CreateEvent(IntPtr.Zero, false, false, "EventActiveSync");                
        while (!terminateDeviceEventThreads)
        {
            //NativeMethods.CeRunAppAtEvent("\\\\.\\Notifications\\NamedEvents\\EventActiveSync", 2);
            //NativeMethods.CeRunAppAtEvent("\\\\.\\Notifications\\NamedEvents\\EventActiveSync", 9);
            NativeMethods.CeRunAppAtEvent("\\\\.\\Notifications\\NamedEvents\\EventActiveSync", 2);                    
            NativeMethods.WaitForSingleObject(handleActiveSyncEndEvent, 0xFFFFFFFF);

            //MessageBox.Show("Activesync ended.");                
            //Do something here

            NativeMethods.CeRunAppAtEvent("\\\\.\\Notifications\\NamedEvents\\EventActiveSync", 0);
            }
        }
        catch (Exception e)
        {
            System.Windows.Forms.MessageBox.Show("Exception in ActiveSyncEndDetect method");
        }
    }

【问题讨论】：

标签： c# compact-framework activesync

【解决方案1】：

我在 Windows CE 5 和 ActiveSync 中注意到了这一点。我不确定这是否是 ActiveSync 问题。您将必须有一个标志来表明它已被摇篮并忽略其他后续消息，直到您检测到从摇篮中移除然后将标志设置回 0 或 false。

【讨论】：

【解决方案2】：

感谢 surfrbum...（我以为我是唯一一个为此苦苦挣扎的人。）你建议的是我以前的方法，但它不是很整洁。

无论如何，这就是我最终设法解决的方法：

while (!terminateDeviceEventThreads)
{
    handleActiveSyncEndEvent = NativeMethods.CreateEvent(IntPtr.Zero,
                                        true, false, "EventActiveSync");
    if (IntPtr.Zero != handleActiveSyncEndEvent)
    {
        if (NativeMethods.CeRunAppAtEvent("\\\\.\\Notifications\\NamedEvents\\EventActiveSync",
                     (int)NOTIFICATION_EVENT.NOTIFICATION_EVENT_RS232_DETECTED))
        {
            NativeMethods.WaitForSingleObject(handleActiveSyncEndEvent, 0xFFFFFFFF);
            if (activeSyncEndDelegateInstance != null)
            {
                OnActiveSyncEnd();
            }
            ResetEvent(handleActiveSyncEndEvent);
            if (!NativeMethods.CeRunAppAtEvent("\\\\.\\Notifications\\NamedEvents\\EventActiveSync",
                             (int)NOTIFICATION_EVENT.NOTIFICATION_EVENT_NONE))
            {
                break;
            }
            handleActiveSyncEndEvent = IntPtr.Zero;
        }
    }
}

所以，遵循这个循环：注册事件，检测引发的事件，自己重置事件，取消注册事件。这样，摇篮检测逻辑就变得非常可靠了。

【讨论】：