How to change BackgroundColor OnMouseHover c++ MFC

Question

I've derived a Window from CWnd in which I create some OwnerDrawn Buttons. The Buttons are derived from CButton.

Now I want to change to BackgroundColor of my Buttons when the User is Hovering over it.

Therefore I already implemented that the OnMouseHover() and the OnMouseLeave() Messages are getting sent:

BEGIN_MESSAGE_MAP(CFooterButton, CButton)
   ON_WM_MOUSEHOVER()
   ON_WM_MOUSEMOVE()
   ON_WM_MOUSELEAVE()
END_MESSAGE_MAP()

void CFooterButton::OnMouseMove(UINT nFlags, CPoint point)
{

   //start tracking of Hover and Leave Event
   TRACKMOUSEEVENT tme;
   tme.cbSize = sizeof(TRACKMOUSEEVENT);
   tme.dwFlags = TME_HOVER | TME_LEAVE;
   tme.hwndTrack = m_hWnd;
   tme.dwHoverTime = HOVER_DEFAULT;
   TrackMouseEvent(&tme);

   CButton::OnMouseMove(nFlags, point);
}


void CFooterButton::OnMouseHover(UINT nFlags, CPoint point)
{


   HDC hdc = *GetWindowDC();

   SetBkColor(hdc,RGB(54, 125, 184));
   CButton::OnMouseHover(nFlags, point);
}

In the Debugger and Spy I can see that the code is getting called but nothing happens. Since I'm relatively new to MFC/c++ I assume I'm not using the DC correctly.. can someone explain me why it is not working and how i can fix it?

Changing the background in `OnMouseHover` wont do much, as the background color is reset when painting the background or the window. You could overwrite `OnEraseBkgn` and set the color there. — Karsten Koop, May 24 '16 at 08:12
@KarstenKoop so I only need to call Invalidate() when OnMouseHover is getting called and then Handle OnEraseBkgn? — Jan Raufelder, May 24 '16 at 08:19
I think a better approach would be to define the button as owner draw and paint the background color using the DC. — rrirower, May 24 '16 at 12:33
You are trying too hard. The button already has all the hover functionality built in. All you have to do is set the `BS_OWNERDRAW` style and override [CButton::DrawItem](https://msdn.microsoft.com/en-us/library/y0k9f0a4.aspx). — IInspectable, May 24 '16 at 13:14

score 1 · Accepted Answer · answered May 24 '16 at 15:36

For anyone else who is struggling my Solution:

Create a member bool m_bHover = false in your Button class
implement OnMouseMove as provided in the Question to Track Hover and Leave

implement OnMouseHover

void CFooterButton::OnMouseHover(UINT nFlags, CPoint point)
{
   m_bHover = true;
   Invalidate();
   CButton::OnMouseHover(nFlags, point);
}

implement OnMouseLeave

void CFooterButton::OnMouseLeave()
{
   m_bHover = false;
   Invalidate();
   CButton::OnMouseHover(nFlags, point);
}

handle Hover effect in yourButtonClass::DrawItem (Invalidate() assures that it'll be called)

void CFooterButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
    //default colors
    COLORREF textColor = RGB(202, 228, 251), backgroundColor = RGB(84, 150, 205);

    switch (lpDrawItemStruct->itemAction)
    {
    case ODA_DRAWENTIRE:
        //check if the user is just hovering over the button
       if (m_isHovered){
             backgroundColor = RGB(54, 125, 184);
             textColor = RGB(255, 255, 255); 
       }
       else{

             backgroundColor = RGB(84, 150, 205);
             textColor = RGB(202, 228, 251);
       }
       break;

    case ODA_FOCUS:
       //Button was clicked incase you want to change sth OnClick
       break;
    }

    CDC dc;
    dc.Attach(lpDrawItemStruct->hDC);
    dc.FillSolidRect(rect, backgroundColor);
    dc.SetTextColor(textColor);

    //your drawing code...
    //DrawFrameControl()etc..
    dc.Detach();
}

Note: The lp-Structure has another itemAction -> ODA_SELECT refer to MSDN https://msdn.microsoft.com/de-de/library/windows/desktop/bb775802(v=vs.85).aspx

`itemAction` is a combination of different flags. You have to check `if (lpDrawItemStruct->itemAction&ODA_DRAWENTIRE)` (for a button this is always true). Also try changing to `tme.dwHoverTime = 10;` for better response. In `OnMouseHover`, change it to `if(!hover){hover=true;Invalidate();}` to reduce consecutive Invalidate calls... — Barmak Shemirani, May 24 '16 at 17:16

How to change BackgroundColor OnMouseHover c++ MFC

1 Answers1