To add a property to your RAD C++ control, you need to invoke the dialog by clicking the right mouse button on the control bitmap on the RadVC toolbox and then selecting "Add Property" context menu item:

The "Add Property" dialog box will now appear.

For our "Circle" control, we will add a property called "CircleShape". "CircleShape" is a Boolean type of property that defines the circular shape of the control. When this property is set as "TRUE", the circle is drawn as a perfect circle. The circle will be drawn within the bounding rectangle of the control. To determine how to draw the circle, you simply calculate he square region centered within the bounding rectangle of the control. When the "CircleShape" property is set to FALSE, an ellipse is drawn.

When Clicked on the "OK" button in "Add Property" dialog, RadVC opens the control implementation file (circle.cpp) and highlighting the "GetCircleShape" function..

BOOL CCircle::GetCircleShape()
{
    return m_CircleShape;
}

void CCircle::SetCircleShape(BOOL bCircleShape)
{
    m_CircleShape = bCircleShape;

   Invalidate();
}

 

void CCircle::DrawControl(CDC* pDC, CRect rect)
{

       if(m_CircleShape)

        {

               int nWidth = rect.Width();

               int nHeight = rect.Height();

               if(nWidth > nHeight)

               {

                     rect.left = (nWidth - nHeight) / 2;

           rect.right = rect.left + nHeight;

               }

     else if(nHeight > nWidth)

               {

                     rect.top = (nHeight - nWidth) / 2;

           rect.bottom = rect.top + nWidth;

               }

        }
        pDC->FillSolidRect(rect, RGB(192, 192, 192));
        pDC->Ellipse(rect);
        pDC->DrawText(_T("C++ Rules!!"), rect, DT_CENTER | DT_VCENTER | DT_SINGLELINE);
}

Next >> Part 6: Adding an Event to the Control

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