如何使用PolyPolygon来绘制多个多边形

[paerxiushi]

小弟在单文档的OnDraw方法中写入如下代码:
CRect rect;
rect.SetRect(100,100,300,300);

CPen pen;
pen.CreatePen(PS_SOLID,1,RGB(255,0,0));
CPen* pOldPen=pDC->SelectObject(&pen);
CBrush brush(RGB(123,34,23));

CBrush* pOldBrush=pDC->SelectObject(&brush);

POINT pt[]={{100,100},{100,150},{150,150},{150,100},{200,200},{200,250},{250,250},{250,200},{45,23}};
int a=4;
pDC->PolyPolygon(pt,&a,2);
pDC->SelectObject(pOldBrush);
pDC->SelectObject(pen);
为什么在调用PolyPolygon方法的返回值是false呢?

[paerxiushi]

没人回答吗？先顶一下。