I have a development based on ATL ocx controls, USB camera preview picture shown in Internet explorer, the underlying DirectShow encapsulated with is in the teacher; , there is now a difficult problem in a web page to initialize - "preview -" closed - "uninstall -" refresh cycle seven times, then 8 times found preview picture didn't, the camera normal open, taking pictures function called can still return the picture, after debugging, found that is ATL m_hWnd NULL value, the camera PostMessage (handle, message... ), the inside of the handle is null, so the preview picture didn't, just close the IE browser to open the can run, ask bosses what reason is this?

CodePudding user response:

For each operation log writing, or remote debugging and see, if there is a window to snap or out of sync problem