Wilson,

You can draw rectange or ellipse with NULL brush:

CBrush* pOldBrush = pDC->SelectStockObject(NULL_BRUSH);
pDC->Rectangle(rect);
pDC->SelectObject(pOldBrush);

>I am drawing a rectangle with the CClientDC in form, how can i draw it transparent.
>
>this also apply to the Ellipse method.