右键弹出菜单项（补充）

//已验证过

void CCadersRosterView::OnContextMenu(CWnd* pWnd, CPoint point)
 {
 //右键弹出菜单项 
CMenu m_datamenu; m_datamenu.LoadMenu(IDR_DATA); CMenu*m_subdatamenu=m_datamenu.GetSubMenu(0);
 CPoint pt;
 GetCursorPos(&pt); 
ASSERT( m_subdatamenu != NULL ); POSITION poslist=m_list.GetFirstSelectedItemPosition();
 if(poslist==NULL) 
{ 
m_subdatamenu->EnableMenuIte(1,MF_GRAYED|MF_BYPOSITION );//MF_BYPOSITION不可少
 m_subdatamenu->EnableMenuItem(2,MF_GRAYED|MF_BYPOSITION ); m_subdatamenu->EnableMenuItem(3,MF_GRAYED|MF_BYPOSITION ); m_subdatamenu->EnableMenuItem(4,MF_GRAYED|MF_BYPOSITION ); m_subdatamenu->EnableMenuItem(5,MF_GRAYED|MF_BYPOSITION );
 }
 m_subdatamenu->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON ,pt.x,pt.y,this);
 m_datamenu.Detach(); 
}