Add checkboxes

A checked list box enables the GUI designer to get the users picked options via a checkbox on every list item. This is well implemented by CCheckListBox in MFC.

How to combine them both into one control?

To use the new features of a list view control you must install IE 3.0 (or above) to get the newest version of COMCTL32.DLL (the common controls library).

This control introduces some new flags in the ListView style and adds accepts some macros defined in the windows header files.

Bear in mind, the new flags and macros DO NOT APPEAR in VC++ 4.2 help files and started to exists in help files only from MSDN Jan 97 version and V++ 5.0

Well, here goes:

First, you have to set the new style in the list view control.

ListView_SetExtendedListViewStyle 
   (m_lvTestList.m_hWnd, LVS_EX_CHECKBOXES | LVS_EX_FULLROWSELECT);

A full description of the new flags follows in this table:

How to get notification when an item is checked / unchecked:

void DemoDlg::OnItemchangedLinksList(NMHDR* pNMHDR, LRESULT* pResult) 
{
	NM_LISTVIEW* pNMListView = (NM_LISTVIEW*)pNMHDR;
	*pResult = 0;

	if (pNMListView->uOldState == 0 && pNMListView->uNewState == 0)
		return;	// 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 (bPrevState == bChecked) // No change in check box
		return;
	
	// Now bChecked holds the new check box state

	// ....
}

ON_NOTIFY(LVN_ITEMCHANGED, IDC_MYLIST, OnItemchangedLinksList)

Setting the check box state of an item:

void SetLVCheck (WPARAM ItemIndex, BOOL bCheck)
{
	ListView_SetItemState (m_lvTestList.m_hWnd, ItemIndex, 
		UINT((int(bCheck) + 1) << 12), LVIS_STATEIMAGEMASK);
}

Getting the check box state of an item:

Email address for Eran Yariv updated on: April 11, 98.