Visual C++ and MFC Programming 2nd Edition

Visual C++ and MFC Fundamentals Chapter 17: Track-Based Controls

5. On the Controls toolbox, click the Picture button and draw a rectangular object
   on the dialog box


6. Change its ID to IDC_PREVIEW


7. Add a CStatic Control variable for the picture object and name it m_Preview


8. In the header file of the CColorPreviewDlg class, declare a private COLORREF
   variable named PreviewColor and a member function named UpdatePreview of
   type void

private:

COLORREF PreviewColor;

void UpdatePreview();

};

9. In the OnInitDialog event of the dialog, initialize the PreviewColor variable with a
   gray color as follows:

PreviewColor = RGB(192, 192, 192);

return TRUE; // return TRUE unless you set the focus to a control

}

10. In the source file of the dialog box, implement the UpdatePreview() method as
    follows:

void CColorPreviewDlg::UpdatePreview()

{

CClientDC dc(this); // device context for painting

// TODO: Add your message handler code here

CBrush BrushBG(PreviewColor);

CRect RectPreview;

m_Preview.GetWindowRect(&RectPreview);

CBrush *pOldBrush = dc.SelectObject(&BrushBG);

ScreenToClient(&RectPreview);

dc.Rectangle(RectPreview);

dc.SelectObject(pOldBrush);

}

11. Save All