Windows Mobile 6.1 / 6.5上具有全局热键的应用程序切换

Question

I'm working on writing an application that straddles the line between C# and C/++ on Windows Mobile 6.1/6.5. We currently have a kiosk application running on our devices, and would like to add the ability to switch back and forth to a second kiosk application.

Our goal is to establish a global hot key that switches process windows (similar to the way that alt+tab works) whenever it is pressed. We already have both applications and I've written some code that switches the processes, but am having a rough time getting the global hot key portion of the project working.

From all of the reading that I've done, my understanding is that the best way to monitor global key presses is to link into the system message pump with the SetWindowsHookEx function in coredll.dll . Unfortunately, I've also read that this function isn't technically supported on the platform.

I also found some tutorials that suggested using a message map with the ON_WM_KEYUP/ON_WM_KEYDOWN macros in the MFC framework, but couldn't find any documentation specific to Windows Mobile. When I tried to use the documentation here , my device kept crashing.

Is there an accepted best practice for setting some kind of global key hook on the platform? If not, is there something that's at least technically supported?

Thanks in advance.

ReplyQuote

Answer 1

Why not use a RegisterHotKey call and use that to swap applications? IIRC the hardware buttons typically map to key codes starting at 0xC1 (193).

Answer 2

We actually ended up polling the GetAsyncKeyState function in coredll.dll on a separate thread. The thread monitors a specific key, and throws an event whenever it is pressed.

Because the event is executed on the key polling thread, you have to be sure to use a delegate to invoke its handler on the GUI thread when the event is thrown.

Answer 3

I would go for a keyboard hook, but only if RegisterHotKey didn't work for your particular scenario.

From all of the reading that I've done, my understanding is that the best way to monitor global key presses is to link into the system message pump with the SetWindowsHookEx function in coredll.dll. Unfortunately, I've also read that this function isn't technically supported on the platform.

Not technically supported, is correct in theory, but I've not seen a WM 6.5.* device that hasn't supported it in reality. Keyboard hooking is such an important feature of vertical market custom rugged WM device apps that it I think it just cannot be removed, for backwards compatibilty.

The enterprise side of the WM space is too important.