CListCtrl的LVN_ITEMCHANGED消息如何判断是选中Item触发的还是取消选中Item触发的

[ranqd]

由选中A改为选中B的时候LVN_ITEMCHANGED消息被触发了3次，1是A的文字背景消失触发，2是A取消选中触发，3是B被选中触发，我如何在响应LVN_ITEMCHANGED消息的函数中判断是哪种情况触发的呢？

[striking]

LRESULT CLeftView::OnItemChanged(NMLISTVIEW* pnmlv)
{
if ((pnmlv->uChanged & LVIF_STATE) &&
(pnmlv->uNewState & LVIS_SELECTED)) {
m_pFormView->SetForm(pnmlv->iItem);
}
return 0;
}
uNewState
Specifies the new item state. This member is zero for notification messages that do not use it.
uOldState
Specifies the old item state. This member is zero for notification messages that do not use it.
uChanged
Set of flags that indicate the item attributes that have changed. This member is zero for notification messages that do not use it. Otherwise, it can have the same values as the mask member of the LVITEM structure.

以上代码是例子