关于OnContextMenu函数的问题

Question

代码如下
void CIpconfigView::OnContextMenu(CWnd* pWnd, CPoint point) 
{
CTreeCtrl* pWndTree = (CTreeCtrl*)this->GetActiveWindow();
ASSERT_VALID (pWndTree); if (point != CPoint (-1, -1))
{
//---------------------
// Select clicked item:
//---------------------
CPoint ptTree = point;
pWndTree->ScreenToClient (&ptTree); HTREEITEM hTreeItem = pWndTree->HitTest (ptTree);
if (hTreeItem != NULL)
{
pWndTree->SelectItem (hTreeItem);
}
} UINT uiMenuResId = 0;
uiMenuResId = IDR_MENU1;
pWndTree->SetFocus ();
     
CMenu popMenu;

popMenu.LoadMenu(uiMenuResId);

GetCursorPos(&point);

popMenu.GetSubMenu(0)->TrackPopupMenu(0,point.x ,point.y,this);
}