Mouse Leave Event in MFC

There is several parts to tracking a mouse leaving, first you need to track on mouse move and a new message, WM_MOUSELEAVE

BEGIN_MESSAGE_MAP(CDerived, CWnd)

ON_WM_MOUSEMOVE()

ON_MESSAGE(WM_MOUSELEAVE, OnMouseLeave)

END_MESSAGE_MAP()

Within the mouse move, you need to setup a new condition to check if we have setup our mouse leave flag:

void

CDerived

::OnMouseMove(UINT nFlags, CPoint point)

{

if (!m_isInClient) // first time we enter, we need to setup the callback

{

TRACKMOUSEEVENT tme = { sizeof(tme) };

tme.dwFlags = TME_LEAVE;

tme.hwndTrack = GetSafeHwnd();

TrackMouseEvent(&tme);

m_isInClient = 1;

}

else if (point == CPoint(-1,-1))

// We are leaving

{

m_isInClient = 0;

}

}

This is the custom message to loop the on mouse leave back to on mouse move:

afx_msg LRESULT OnMouseLeave(WPARAM,LPARAM)

{

OnMouseMove(0,CPoint(-1,-1));

return 0;

}