昨天在研究mobile上挂机的时侯，发现了这么一个消息。不过这个消息与挂机没有什么关联。只是在其他界面遮盖对话框的时候会产生这个消息。
下面我们来看一下这个消息的介绍，摘自SDK。

WM_CANCELMODE

功能描述：
This message is sent to the focus window when a dialog box or message box is displayed; this enables the focus window to cancel modes, such as stylus capture.

返回值：
An application should return zero if it processes this message.

这里还有一些相关的信息：

摘自：http://support.microsoft.com/kb/74548/en-us/

In the Microsoft Windows graphical environment, the WM_CANCELMODE message informs a window that it should cancel any internal state. This message is sent to the window with the focus when a dialog box or a message box is displayed, giving the window the opportunity to cancel states such as mouse capture.

When a control has the focus, it receives a WM_CANCELMODE message when the EnableWindow function disables the control or when a dialog box or a message box is displayed. When a control receives this message, it should cancel modes, such as mouse capture, and delete any timers it has created. A control must cancel these modes because an application may use a notification from the control to display a dialog box or a message box.

The DefWindowProc function processes WM_CANCELMODE by calling the ReleaseCapture function, which cancels the mouse capture for whatever window has the capture. The DefWindowProc function does not cancel any other modes.

原来想尝试一下别的窗口遮盖住对话框后做一些操作，这个消息似乎是一遮盖就发出了，不起作用。原来我把这个消息想得太好了。

呼呼，不用了