UINT BCGM_ON_PREPARE_TASKBAR_PREVIEW

This message is sent to a CView object when the framework needs to display a preview of the view on Windows 7/8/10 task bar.

Parameters

wParam	HDC of an off-screen window used to display the preview image.
lParam	this parameter is not used.

Returns

should return non-zero if the message is handled at the application level.

Process this message (usually in a CView - derived class) to implement custom preview by drawing on the HDC taken from wParam. The default handler displays the current CView content by sending WM_PRINT message to the view.