CListCtrl and sorting rows

#include "stdafx.h"

#include "CListCtrl_SortItems.h"

BEGIN_MESSAGE_MAP(CListCtrl_SortItems, CListCtrl)
	ON_NOTIFY_REFLECT_EX(LVN_GETDISPINFO, OnGetDispInfo)	// Text Callback
	ON_NOTIFY_REFLECT_EX(LVN_COLUMNCLICK, OnHeaderClick)	// Column Click
END_MESSAGE_MAP()

BOOL CListCtrl_SortItems::OnGetDispInfo(NMHDR* pNMHDR, LRESULT* pResult)
{
	NMLVDISPINFO* pNMW = reinterpret_cast<NMLVDISPINFO*>(pNMHDR);
	int nItem = pNMW->item.iItem;
	int nSubItem = pNMW->item.iSubItem;

	if (nItem< 0 || nItem >= GetItemCount())
		return FALSE;	// requesting invalid item

	if (nSubItem < 0 || nSubItem >= GetHeaderCtrl()->GetItemCount())
		return FALSE;	// requesting invalid column

	int col = GetColumnData(nSubItem);
	size_t rowId = (size_t)GetItemData(nItem);

	if(pNMW->item.mask & LVIF_TEXT)
	{
		// Request text
		const string& result = m_DataModel.GetCellText(rowId, col);
		_tcsncpy(pNMW->item.pszText, result.c_str(), pNMW->item.cchTextMax);
	}

	return FALSE;	// Let parent-dialog get chance
}

namespace {
	struct PARAMSORT
	{
		PARAMSORT(const CListCtrl_DataModel& datamodel, int columnData, bool ascending)
			:m_DataModel(datamodel)
			,m_ColumnData(columnData)
			,m_Ascending(ascending)
		{}

		const CListCtrl_DataModel& m_DataModel;
		int  m_ColumnData;
		bool m_Ascending;
	};

	// Comparison extracts values from the DataModel
	int CALLBACK SortFunc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
	{
		PARAMSORT& ps = *(PARAMSORT*)lParamSort;

		const string& left = ps.m_DataModel.GetCellText((size_t)lParam1, ps.m_ColumnData);
		const string& right = ps.m_DataModel.GetCellText((size_t)lParam2, ps.m_ColumnData);

		if (ps.m_Ascending)
			return _tcscmp( left.c_str(), right.c_str() );	
		else
			return _tcscmp( right.c_str(), left.c_str() );					
	}
}

bool CListCtrl_SortItems::SortColumn(int columnIndex, bool ascending)
{
	if (GetItemCount()!=m_DataModel.GetRowIds())
		return false;

	int columnData = GetColumnData(columnIndex);
	PARAMSORT paramsort(m_DataModel, columnData, ascending);
	SortItems(SortFunc, (DWORD_PTR)&paramsort);
	return true;
}

void CListCtrl_SortItems::LoadData()
{
	if (GetHeaderCtrl()->GetItemCount()==0)
	{
		// Create Columns
		for(int col = 0; col < m_DataModel.GetColCount() ; ++col)
		{
			const string& title = m_DataModel.GetColTitle(col);
			VERIFY( InsertColumn(col, title.c_str(), LVCFMT_LEFT, 100) != -1 );
		}
	}
	else
	{
		// Empty list-control and force refresh
		DeleteAllItems();
		ResetSortOrder();
		Invalidate();
		UpdateWindow();
	}

	// Insert data with callback
	SetRedraw(FALSE);	// Disable redraw as InsertItem becomes so much faster
	int nItem = 0;
	for(size_t rowId = 0; rowId < m_DataModel.GetRowIds() ; ++rowId)
	{
		nItem = InsertItem(++nItem, "");	// Fastest to insert at the end
		VERIFY(nItem!=-1);
		VERIFY(SetItemData(nItem, rowId));
		for(int col = 0; col < m_DataModel.GetColCount() ; ++col)
		{
			VERIFY(SetItemText(nItem, col, LPSTR_TEXTCALLBACK));
		}
	}
	SetRedraw(TRUE);
	Invalidate();
	UpdateWindow();
}