Using Check Box in List Control

• Download source files - 2.98 KB
• Download demo project - 63.25 KB

Introduction

It's easy to add check box in List Control, but the check box is only added in the list's items, not in the head items, and also you could not select or de-select all items in the list by one hit.

This article discusses a method which adds a check box in head items, and could use this check box to select or de-select all items in the list.

Steps

1. Adding Check Box for List Control

It's fairly easy. Just set the extended style: LVS_EX_CHECKBOXES.

m_listCtrl.SetExtendedStyle( m_listCtrl.GetExtendedStyle() | LVS_EX_CHECKBOXES);

2. Adding Check Box for Head Ctrl

First, we must create a Image list which contains the check box bitmap, and then set the image list to headctrl, finally we need to set the image for first head item using CHeadCtrl::setItem.

CHeaderCtrl* pHeadCtrl = this->GetHeaderCtrl();
ASSERT(pHeadCtrl->GetSafeHwnd());

VERIFY( m_checkHeadCtrl.SubclassWindow(pHeadCtrl->GetSafeHwnd()) );
VERIFY( m_checkImgList.Create(IDB_CHECKBOXES, 16, 3, RGB(255,0,255)));
int i = m_checkImgList.GetImageCount();
m_checkHeadCtrl.SetImageList(&m_checkImgList);
    
HDITEM hdItem;
hdItem.mask = HDI_IMAGE | HDI_FORMAT;
VERIFY( m_checkHeadCtrl.GetItem(0, &hdItem) );
hdItem.iImage = 1;
hdItem.fmt |= HDF_IMAGE;
    
VERIFY( m_checkHeadCtrl.SetItem(0, &hdItem) );

3. Using Check Box in headctrl to Select or De-select All Items in List

We need to respond to the HDN_ITEMCLICK notification message of headctrl by either notify or notify reflect mechanism. I choose notify reflect.

BEGIN_MESSAGE_MAP(CCheckHeadCtrl, CHeaderCtrl)
    //{{AFX_MSG_MAP(CCheckHeadCtrl)
    ON_NOTIFY_REFLECT(HDN_ITEMCLICK, OnItemClicked)
    // NOTE - the ClassWizard will add and remove mapping macros here.
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CCheckHeadCtrl message handlers
void CCheckHeadCtrl::OnItemClicked(NMHDR* pNMHDR, LRESULT* pResult)
{
    NMHEADER* pNMHead = (NMHEADER*)pNMHDR;
    *pResult = 0;

    int nItem = pNMHead->iItem;
    if (0 != nItem)
        return;

    HDITEM hdItem;
    hdItem.mask = HDI_IMAGE;
    VERIFY( GetItem(nItem, &hdItem) );

    if (hdItem.iImage == 1)
        hdItem.iImage = 2;
    else
        hdItem.iImage = 1;

    VERIFY( SetItem(nItem, &hdItem) );
    
    BOOL bl = hdItem.iImage == 2 ? TRUE : FALSE;
    CListCtrl* pListCtrl = (CListCtrl*)GetParent();
    int nCount = pListCtrl->GetItemCount();    
    for(nItem = 0; nItem < nCount; nItem++)
    {
        ListView_SetCheckState(pListCtrl->GetSafeHwnd(), nItem, bl);
    }    
}

4. Change the Head's Check Status When the Check Status Changed in List Control

We need to respond to the notification message LVN_ITEMCHANGED of list control.

BEGIN_MESSAGE_MAP(CCheckListCtrl, CListCtrl)
    //{{AFX_MSG_MAP(CCheckListCtrl)
    ON_NOTIFY_REFLECT(LVN_ITEMCHANGED, OnItemChanged)        
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CCheckListCtrl message handlers
void CCheckListCtrl::OnItemChanged(NMHDR* pNMHDR, LRESULT* pResult)
{
    NMLISTVIEW* pNMLV = (NMLISTVIEW*)pNMHDR;
    *pResult = 0;

    if ( m_blInited && LVIF_STATE == pNMLV->uChanged)
    {
        BOOL blAllChecked = TRUE;
        int nCount = GetItemCount();
        for(int nItem = 0; nItem < nCount; nItem++)
        {
            if ( !ListView_GetCheckState(GetSafeHwnd(), nItem) )
            {
                blAllChecked = FALSE;
                break;
            }
        }
        
        HDITEM hdItem;
        hdItem.mask = HDI_IMAGE;
        if (blAllChecked)
            hdItem.iImage = 2;
        else
            hdItem.iImage = 1;
        VERIFY( m_checkHeadCtrl.SetItem(0, &hdItem) );
    }
}

Demo Project

It is a dialog based application that covers all I mentioned in this article. You could inspect it in your environment.

History

• 27^th March, 2006: Initial post