终于找到第二个圆绘不出来的原因

BEGIN_MSG_MAP(CODButtonImpl)
CHAIN_MSG_MAP_ALT(COwnerDraw<CODButtonImpl>, 1)
MSG_WM_ERASEBKGND(OnEraseBkGnd)
DEFAULT_REFLECTION_HANDLER()
END_MSG_MAP()

LRESULT OnEraseBkGnd(HDC hDC)
{
CDC dc(hDC);// CDCHandle dc(hDC);
return 1;
}

void DrawItem ( LPDRAWITEMSTRUCT lpdis )
{
RECT rc = lpdis->rcItem;
CDCHandle hdc = lpdis->hDC;

CDC dc(lpdis->hDC);

CPen pen;
pen.CreatePen(0,1,RGB(28,81,128));
HPEN hOldPen = dc.SelectPen(pen);
HBRUSH hOldBrush = dc.SelectStockBrush(WHITE_BRUSH);
dc.Ellipse(&rc);
}
原来是红色的那行，它用CDC来管理hDC，用完后就释放hDC了。改成CDCHandle就好了。