ON_WM_MOUSEHOVER消息要生效,要配合ON_WM_MOUSEMOVE一起使用.代码如下:

void CYuButton::OnMouseMove(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	TRACKMOUSEEVENT  tme = { 0 };
	tme.cbSize = sizeof(TRACKMOUSEEVENT);
	tme.dwFlags = TME_HOVER | TME_LEAVE;
	tme.dwHoverTime = 50;
	tme.hwndTrack = this->m_hWnd;
	if (TrackMouseEvent(&tme)) {}

	CWnd::OnMouseMove(nFlags, point);
}
void CYuButton::OnMouseHover(UINT nFlags, CPoint point)
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	m_bIsDown = TRUE;
	Invalidate();
	CWnd::OnMouseHover(nFlags, point);
}

以上是鼠标放在控件上时的消息响应.鼠标离开控件直接处理ON_WM_MOUSELEAVE消息,如:

void CYuButton::OnMouseLeave()
{
	// TODO: 在此添加消息处理程序代码和/或调用默认值
	m_bIsDown = FALSE;
	Invalidate();
	CWnd::OnMouseLeave();
}

也可同时处理失去焦点消息ON_WM_KILLFOCUS,如下:

void CYuButton::OnKillFocus(CWnd* pNewWnd)
{
	CWnd::OnKillFocus(pNewWnd);
	m_bIsDown = TRUE;
	Invalidate(TRUE);
}