C / C++ / MFC

// Handle the ItemChanged message.
void CMyDlg::OnItemchangedListParts(NMHDR* pNMHDR, LRESULT* pResult) 
{
	NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;
	*pResult = 0;
 
	if (HasCheckboxChanged(pNMListView))
		UpdateControls();
}
 
// Check if the checkbox in the given item has changed.
bool CMyDlg::HasCheckboxChanged(NM_LISTVIEW* pNMListView, bool* pbChecked = NULL) const
{
	ASSERT(pNMListView);
 
	if (pNMListView->uOldState == 0 && pNMListView->uNewState == 0)
		return false; // No change
 
	BOOL bPrevState = (BOOL)(((pNMListView->uOldState & LVIS_STATEIMAGEMASK)>>12) - 1);   // Old check box state
	if (bPrevState < 0)     // On startup there's no previous state 
		bPrevState = 0; // so assign as false (unchecked)
 	
	// New check box state
	BOOL bChecked=(BOOL)(((pNMListView->uNewState & LVIS_STATEIMAGEMASK)>>12) - 1);   
	if (bChecked < 0) // On non-checkbox notifications assume false
		bChecked = 0; 
 
	if (pbChecked)
		*pbChecked = !!bChecked;		
	return (bPrevState != bChecked);
}