MFC基于对话框

[lmy11111]

点了画图按钮后没反映，不能画出圆形，怎么改啊
void CMy2012310200825Dlg::OnDraw()
{
// TODO: Add your control notification handler code here
double x,y;

CPaintDC dc(this);
HPEN hPen;
HBRUSH hBr;
hPen=(HPEN)GetStockObject(BLACK_PEN);
hBr=(HBRUSH)GetStockObject(BLACK_BRUSH);
SelectObject(dc,hPen);
SelectObject(dc,hBr);
for(int i=1;i<m_n;i++)
{
x=150*sin(i*2*pi/m_n);
y=150*cos(i*2*pi/m_n);
Ellipse(dc,150-x,150-y,165-x,165-y); //画圆
}
DeleteObject(hPen);
DeleteObject(hBr);
UpdateData(FALSE);
}

[yaozhiyong110]

UpdateData(FALSE); -> invalidate();