Sort list (numeric/text/float/date) using callback

One of my friends refered me to your site. I like it! I have looked for an easy solution to sort a List control and found several recepies on your site. Unfortunately, there was no nice, elegant, and general solution there, so I took "Sort list (numeric/text) using callback" article by Appolonio and redid it. Here is much more elegant class that in addition to text and numeric will also sort float and time columns and is extensible to other types. I hope, someone will benefit from it.
////////////////////////////////////////////////////////////////////////  
////////
// by Max Poliashenko - rewritten version of class proposed by Iuri Applonio
// This class will sort a List control by a column of text, integer, float or
// date/time type. It could be easily extended for other data types.
// February 11, 1998
//

class CSortClass
{
public:
	enum EDataType {dtNULL, dtINT, dtSTRING, dtDATETIME, dtDEC};
	
	CSortClass(CListCtrl * _pWnd, const int _iCol);
	virtual ~CSortClass();
	void Sort(bool bAsc, EDataType _dtype);
	
protected:
	CListCtrl * pWnd;
	
	static int CALLBACK Compare(LPARAM lParam1, LPARAM lParam2, LPARAM 
		lParamSort);
	
	struct CSortItem
	{
		CSortItem(const DWORD _dw, const CString &_txt);
		DWORD dw; 
		CString txt;
	};
};


////////////////////////////////////////////////////////////////////////  
/////
// CSortClass

CSortClass::CSortClass(CListCtrl * _pWnd, const int _iCol)
{
	pWnd = _pWnd;
	
	ASSERT(pWnd);
	int max = pWnd->GetItemCount();
	DWORD dw;
	CString txt;
	
	// replace Item data with pointer to CSortItem structure
	for (int t = 0; t < max; t++)
	{
		dw = pWnd->GetItemData(t); // save current data to restore it later
		txt = pWnd->GetItemText(t, _iCol); 
		pWnd->SetItemData(t, (DWORD) new CSortItem(dw, txt));
	}
}

CSortClass::~CSortClass()
{
	ASSERT(pWnd);
	int max = pWnd->GetItemCount();
	CSortItem * pItem;
	for (int t = 0; t < max; t++)
	{
		pItem = (CSortItem *) pWnd->GetItemData(t);
		ASSERT(pItem);
		pWnd->SetItemData(t, pItem->dw);
		delete pItem;
	}
}

void CSortClass::Sort(bool _bAsc, EDataType _dtype)
{
	long lParamSort = _dtype;
	
	// if lParamSort positive - ascending sort order, negative - descending
	if (!_bAsc)
		lParamSort *= -1; 
	
	pWnd->SortItems(Compare, lParamSort);
}

int CALLBACK CSortClass::Compare(LPARAM lParam1, LPARAM lParam2, LPARAM 
								 lParamSort)
{
	CSortItem * item1 = (CSortItem *) lParam1;
	CSortItem * item2 = (CSortItem *) lParam2;
	ASSERT(item1 && item2);
	
	// restore data type and sort order from lParamSort
	// if lParamSort positive - ascending sort order, negative - descending
	short   sOrder = lParamSort < 0 ? -1 : 1; 
	EDataType dType  = (EDataType) (lParamSort * sOrder); // get rid of sign
	
	// declare typed buffers
	COleDateTime t1, t2;
	
	switch (dType)
	{
	case  EDataType::dtINT:
		return (atol(item1->txt) - atol(item2->txt))*sOrder;
	case  EDataType::dtDEC:
		return (atof(item1->txt) < atof(item2->txt) ? -1 : 1)*sOrder;
	case  EDataType::dtDATETIME:
		if (t1.ParseDateTime(item1->txt) && t2.ParseDateTime(item2->txt))
			return (t1 < t2 ? -1 : 1 )*sOrder;
		else
			return 0;
	case  EDataType::dtSTRING:
		return item1->txt.CompareNoCase(item2->txt)*sOrder;
		
	default:
		ASSERT("Error: attempt to sort a column without type.");
		return 0;
	}
}


CSortClass::CSortItem::CSortItem(const DWORD _dw, const CString & _txt)
{
	dw  = _dw;
	txt = _txt;
}

==========================================================================
Here is its usage:

void CMyDlg::OnHeaderClicked(NMHDR* pNMHDR, LRESULT* pResult)
{
	static int  nSortedCol = -1;
	static bool bSortAscending = true; 
	
	HD_NOTIFY *phdn = (HD_NOTIFY *) pNMHDR;
	
	if( phdn->iButton == 0 )
	{
		// User clicked on header using left mouse button
		if( phdn->iItem == nSortedCol )
			bSortAscending = !bSortAscending;
		else
			bSortAscending = TRUE;
		
		nSortedCol = phdn->iItem;
		
		CSortClass csc(&m_List, nSortedCol);
		
		csc.Sort(bSortAscending, (CSortClass::EDataType) 
			m_arrColType[nSortedCol]); 
	}
	*pResult = 0;
}

Posted: March, 8, 98

Comments:



Comments

  • Elegant work

    Posted by turkim on 11/20/2010 05:21pm

    Thanks for your effort .. you really saved me days of work. And thanks also to hanhao who gave us a big help.

    Reply
  • solving problem with m_arrColType

    Posted by hanhao on 07/05/2005 12:49am

    after tons of researching the code and checking it out, i found the correct solution http://www.codeguru.com/forum/showthread.php?p=1186557#post1186557 [CODE]// SortClass.h: interface for the CSortClass class. // ////////////////////////////////////////////////////////////////////// #if !defined(AFX_SORTCLASS_H__C4FFD42B_9BC4_4084_AA1C_DAA42CDCC697__INCLUDED_) #define AFX_SORTCLASS_H__C4FFD42B_9BC4_4084_AA1C_DAA42CDCC697__INCLUDED_ #if _MSC_VER > 1000 #pragma once #endif // _MSC_VER > 1000 class CSortClass { public: enum EDataType {dtNULL, dtINT, dtSTRING, dtDATETIME, dtDEC}; CSortClass(CListCtrl * _pWnd, const int _iCol); virtual ~CSortClass(); void Sort(bool bAsc, EDataType _dtype); EDataType m_arrColType[200]; [COLOR=DarkOrange]THIS IS CORRECT![/COLOR] protected: CListCtrl * pWnd; EDataType m_arrColType[200]; [COLOR=Sienna]THIS IS WRONG[/COLOR] static int CALLBACK Compare(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort); struct CSortItem { CSortItem(const DWORD _dw, const CString &_txt); DWORD dw; CString txt; }; }; #endif // !defined(AFX_SORTCLASS_H__C4FFD42B_9BC4_4084_AA1C_DAA42CDCC697__INCLUDED_)[/CODE]

    • (2) solving problem with m_arrColType

      Posted by hanhao on 07/05/2005 12:51am

      http://www.codeguru.com/forum/showthread.php?p=1186557#post1186557

      Reply
    Reply
  • WHAT IS m_arrColType!?!??

    Posted by hanhao on 06/23/2005 03:17pm

    WHAT IS m_arrColType!?!??

    Reply
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