CListViewCtrl creation does not produce column header arrow indicating sort order

[Jonathan Davies]

I have a Dialog, inheriting from CDialogImpl, which contains a CListViewCtrl with three columns. In order to get the list items ordered correctly a custom sort function is used. It is in my handler for LVN_COLUMNCLICK< (Clicking a column header) that that the column header has the triangular bitmap indicating sort direction set. On creation of the dialog, without the workaround shown below, no sort direction arrow appears on the header. I then have to call the LVN_COLUMNCLICK handler (see code) from OnInitDialog to force a sort of the first column in the order that my LVN_COLUMNCLICK handler sets the sort order triangular bitmap in the column header.

LRESULT CPortsDlg::OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
{
...

// Work-around to force list control to sort column 0 ascending on creation
int idCtrl = 0;
NMLISTVIEW nmlv;
nmlv.iSubItem = 0;
BOOL bHandled = FALSE;
LPNMHDR lpNMHDR = reinterpret\_cast<LPNMHDR>(&nmlv);
OnLvnColumnclick(idCtrl, lpNMHDR, bHandled); 

    return 0;

}

This doesn't seem right; am I missing some feature that will ensure that upon creation a particular list column is sorted (using my custom sort) in, say, ascending order with the appropriate column header bitmap displayed to indicate this?

LRESULT CPortsDlg::OnLvnColumnclick(int /*idCtrl*/, LPNMHDR pNMHDR, BOOL& /*bHandled*/)
{
// Get some calls where m_hwnd is 0
if(!::IsWindow(m_hWnd))
{
return 0;
}

// ListView  Notification Message structure
LPNMLISTVIEW pNMLV = reinterpret\_cast<LPNMLISTVIEW>(pNMHDR); 

// Want the format of the list column header
HDITEM HeaderItem; 
HeaderItem.mask = HDI\_FORMAT; 

// Attach a CHeaderCtrl to this CListViewCtrl's header
CHeaderCtrl HeaderCtrl = m\_ListViewCtrl.GetHeader(); 

if(!::IsWindow(HeaderCtrl.m\_hWnd))
{
	return 0;
}

// For each list column...
int nColumnCount = HeaderCtrl.GetItemCount();
for(int nSelectedColumn = 0; nSelectedColumn < nColumnCount; nSelectedColumn++)
{
	// Get the format for the sub-item (column)
	HeaderCtrl.GetItem(nSelectedColumn, &HeaderItem); 

	// Remove any up/down arrow from this column
	HeaderItem.fmt &= ~(HDF\_SORTDOWN | HDF\_SORTUP);

	if(nSelectedColumn == pNMLV->iSubItem)
	{
		// If this is a different column from any selected before use an up-arrow otherwise
		// base it on changing the direction from m\_S

[Stuart Dootson]

It doesn't seem unreasonable to me that you have to tell the control how it's sorted - I suspect that setting HDF_SORTDOWN or HDF_SORTUP on the relevant column and calling m_ListViewCtrl.SortItems would be sufficient - if that's the case, maybe you should refactor the header flag setting and control sorting into a separate function, so it could be called from OnInitDialog rather than calling the OnClick handler? [edit]Maybe CSortListViewCtrl will do some of the sorting tasks for you, simplifying the overall job?[/edit]

[Jonathan Davies]

Stuart, I've done a test using CSortListViewCtrl (which I didn't know about) instead of CListViewCtrl. It seems that simply calling SetSortColumn(0) both makes my handler for LVN_COLUMNCLICK redundant and removes the need to call it from InitDialog. I haven't tried this with a custom sort yet but can see I will need to call SetColumnSortType(0, LVCOLSORT_CUSTOM). Much neater. Thanks.