Question

On subclassing CButton, I want the color of the button to increment each time the button is pressed. But the following is doing nothing to the background color. However, the text shows “c” to increment. thx

void CMyButton::OnLButtonDown(UINT nFlags, CPoint point) 
{
    CButton::OnLButtonDown(nFlags, point);
    static int c;

    CString s;
    s.Format("left:  %d", c*50);
    this->SetWindowText(s);

  ////// Neither of the following change the background color   
    //CPaintDC dc(this);
    //dc.SetBkColor(0x0 + c*50);
    CDC *dc= GetDC();
    dc->SetBkColor(0x0 + c*50);

    c++;
}

Answer 1

If you want to change how your button is drawn, you should implement CMyButton::DrawItem (overriding CButton::DrawItem), and do the drawing there. In OnLButtonDown, you’ll just do something like:

c++; 
Invalidate();

You’ll want c to be a member of CMyButton, not local to OnLButtonDown.