MFC OnPaint() vs OnDraw()

The two are more or less the same. OnPaint is the handler for a WM_PAINT message. OnDraw is the function that a MFC CView window calls when it receives a WM_PAINT message. 

We should use OnDraw if the window is derived from CView, otherwise OnPaint.

OnDraw()	OnPaint()
A member function of CView. OnDraw is a virtual function.  OnPaint handler for views call a virtual function OnDraw. CView::OnDraw virtual void OnDraw(     CDC* pDC   ) = 0 pDC Points to the device context to be used for rendering an image of the document.	A member function of CWnd. OnPaint is a WM_PAINT message handler. CWnd::OnPaint afx_msg void OnPaint( );