but when call at some dlg,only no echo,but after add a Invalidate() ,it will be ok very strange.

void CAboutDlg::OnTestDraw()
{      Invalidate();
       CPaintDC dc(this);
    CPen MyNewPen;
    COLORREF mm_color=RGB(233,44,55);//dlg.m_color;
    MyNewPen.CreatePen(PS_SOLID,10,mm_color);//RGB(255,0,0)
    CPen* pOriginalPen;
    pOriginalPen=dc.SelectObject(&MyNewPen);
       int m_Radius=22;
    CRect MyRectangle(30,10,20+m_Radius*2,10+m_Radius*2);
    dc.Ellipse(&MyRectangle);
    dc.LineTo(235,444);
    dc.SelectObject(pOriginalPen);
    //CDialog::OnPaint();
 
}