可以读取图像大小来设置 m_iconX,m_iconY的值，这里是固定为20，如果图像过大就显示不出
BOOL Cxxx::GetBitmapFromImageList(CDC* pDC,CImageList *imglist,int nIndex,CBitmap &bmp)
{
int m_iconX=20;
int m_iconY=20;
HICON hIcon = imglist->ExtractIcon(nIndex);
CDC dc;
dc.CreateCompatibleDC(pDC);
bmp.CreateCompatibleBitmap(pDC,m_iconX,m_iconY);
CBitmap* pOldBmp = dc.SelectObject(&bmp);
CBrush brush ;
brush.CreateSolidBrush(GetSysColor(COLOR_MENU));
::DrawIconEx(dc.GetSafeHdc(),0, 0,hIcon,m_iconX,m_iconY,0,(HBRUSH)brush,DI_NORMAL);
dc.SelectObject( pOldBmp );
dc.DeleteDC();
// the icon is not longer needed
DestroyIcon(hIcon);
return(TRUE);
}