BCGControlBar Pro for MFC
UINT BCGM_ONWINDOWSAPPMODECHANGED

The BCGM_ONWINDOWSAPPMODECHANGED message is sent to the main application window when Windows app mode is changed.

Parameters
wParamNon-zero if Windows app mode is dark, zero - light.
lParamthis parameter is not used.
Returns
the return value is ignored.