hlistbox.cpp

这是树上的代码

//****************************************************************************
// File:
//
//     HListBox.cpp
//
// Purpose:
//
//     Implementation file for class CHListBox.
//
// Functions:
//
//  CHListBox::CHListBox             Constructs a CHListBox
//  CHListBox::~CHListBox            Destructor
//  CHListBox::LockHExtentUpdate     Pauses automatic updating of the horizontal scroll bar
//  CHListBox::UnlockHExtentUpdate   Restores automatic updating of the horizontal scroll bar
//  CHListBox::UpdateHExtent         Updates the horizontal scroll bar extent after LockHExtentUpdate has been called
//  CHListBox::InsertNewExtent       Internal utility function used to maintain the extent array
//  CHListBox::InitTabStops          Internal tab stop init function
//  CHListBox::OnAddString           Intercepts LB_ADDSTRING msg
//  CHListBox::OnInsertString        Intercepts LB_INSERTSTRING msg
//  CHListBox::OnDeleteString        Intercepts LB_DELETESTRING msg
//  CHListBox::OnSetTabStops         Intercepts LB_SETTABSTOPS msg
//
// Development Team:
//
//     James Rhodes
//
// Written by Microsoft Product Support Services, Languages Developer Support
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
//****************************************************************************

#include "stdafx.h"
#include "HListBox.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

//////////////////////////////////////////////////////////////////////////////
// CHListBox

//****************************************************************************
// Function:
//
//     CHListBox::CHListBox()
//
// Purpose:
//
//     Constructs a CHListBox object
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
CHListBox::CHListBox()
{
	m_bLocked = FALSE;      // start out in auto mode
	m_nLongestExtent = 0;   // tracks longest extent, initially 0
	m_nTabStops = 0;        // no tab stops
	m_lpTabStops = NULL;    // array of tab stops
}

//****************************************************************************
// Function:
//
//     CHListBox::~CHListBox()
//
// Purpose:
//
//     Destructs a CHListBox object
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
CHListBox::~CHListBox()
{
	if (m_lpTabStops != NULL)
		delete m_lpTabStops;
}

//****************************************************************************
// Function:
//
//     CHListBox::LockHExtentUpdate()
//
// Purpose:
//
//     Stops auto updating of horizontal extent
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
void CHListBox::LockHExtentUpdate()
{
	m_bLocked = TRUE;
}

//****************************************************************************
// Function:
//
//     CHListBox::UnlockHExtentUpdate()
//
// Purpose:
//
//     Turns auto updating back on
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
void CHListBox::UnlockHExtentUpdate()
{
	m_bLocked = FALSE;
}

//****************************************************************************
// Function:
//
//     CHListBox::UpdateHExtent()
//
// Purpose:
//
//     Updates horizontal extent when auto updating has been turned off
//     for some period.
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
void CHListBox::UpdateHExtent()
{
	m_arrExtents.RemoveAll();
	m_nLongestExtent = 0;
	int nCount = GetCount();

	CDC* pDC = GetDC();
	HFONT hFont = (HFONT)SendMessage(WM_GETFONT);
	CFont *pFont = CFont::FromHandle(hFont);
	ASSERT (pFont);
	CFont *pPrevFont = pDC->SelectObject(pFont);

	CString csValue;
	for (int i=0; i<nCount; i++)
	{
		GetText(i, csValue);
		InsertNewExtent(i, csValue, pDC);
	}
	SetHorizontalExtent(m_nLongestExtent);
	pDC->SelectObject(pPrevFont);
	ReleaseDC(pDC);
}

//****************************************************************************
// Function:
//
//     CHListBox::InsertNewExtent() PROTECTED
//
// Purpose:
//
//     Used to update the extent array when a new item is added
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
void CHListBox::InsertNewExtent(int nItem, LPCTSTR lpszStr, CDC* pDC)
{
	if (NULL==m_lpTabStops)
		InitTabStops();

    CSize newExtent;
    if (GetStyle() & LBS_USETABSTOPS)
	    newExtent = pDC->GetTabbedTextExtent(lpszStr, strlen(lpszStr), m_nTabStops, m_lpTabStops);
    else
        newExtent = pDC->GetTextExtent(lpszStr, strlen(lpszStr));

	newExtent.cx += 6;
	m_arrExtents.InsertAt(nItem, newExtent.cx);

	if (newExtent.cx>m_nLongestExtent)
		m_nLongestExtent = newExtent.cx;
}

void CHListBox::InsertNewExtent(int nItem, LPCTSTR lpszStr)
{
	if (m_bLocked) return;

	CDC* pDC = GetDC();
	HFONT hFont = (HFONT)SendMessage(WM_GETFONT);
	CFont *pFont = CFont::FromHandle(hFont);
	ASSERT (pFont);
	CFont* pPrevFont = pDC->SelectObject(pFont);
	InsertNewExtent(nItem, lpszStr, pDC);
	SetHorizontalExtent(m_nLongestExtent);
	pDC->SelectObject(pPrevFont);
	ReleaseDC(pDC);
}

//****************************************************************************
// Function:
//
//     CHListBox::InitTabStops() PROTECTED
//
// Purpose:
//
//     Initializes tab stops
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
void CHListBox::InitTabStops()
{
	int nDefault = 2;
	SetTabStops(1, &nDefault);
}

BEGIN_MESSAGE_MAP(CHListBox, CListBox)
	//{{AFX_MSG_MAP(CHListBox)
	//}}AFX_MSG_MAP
	ON_MESSAGE( LB_ADDSTRING, OnAddString )
	ON_MESSAGE( LB_INSERTSTRING, OnInsertString )
	ON_MESSAGE( LB_DELETESTRING, OnDeleteString )
	ON_MESSAGE( LB_SETTABSTOPS, OnSetTabStops )
END_MESSAGE_MAP()

//////////////////////////////////////////////////////////////////////////////
// CHListBox message handlers

//****************************************************************************
// Function:
//
//     CHListBox::OnAddString()
//
// Purpose:
//
//     Intercepts the LB_ADDSTRING message to update the horizontal extent
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
LRESULT CHListBox::OnAddString(WPARAM, LPARAM lParam)
{
	LRESULT lResult = Default();
	if (LB_ERR==lResult || LB_ERRSPACE==lResult)
		return lResult;
	InsertNewExtent(lResult, (LPCTSTR)lParam);

	return lResult;
}

//****************************************************************************
// Function:
//
//     CHListBox::OnInsertString()
//
// Purpose:
//
//     Intercepts the LB_INSERTSTRING message to update the horizontal extent
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
LRESULT CHListBox::OnInsertString(WPARAM, LPARAM lParam)
{
	LRESULT lResult = Default();
	if (LB_ERR==lResult || LB_ERRSPACE==lResult)
		return lResult;
	InsertNewExtent(lResult, (LPCTSTR)lParam);

	return lResult;
}

//****************************************************************************
// Function:
//
//     CHListBox::OnDeleteString()
//
// Purpose:
//
//     Intercepts the LB_DELETESTRING message to update the horizontal extent
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
LRESULT CHListBox::OnDeleteString(WPARAM wParam, LPARAM)
{
	LRESULT lResult = Default();
	if (LB_ERR==lResult)
		return lResult;

	if (m_bLocked) return lResult;

	int nExtent = m_arrExtents[wParam];
	m_arrExtents.RemoveAt(wParam);
	if (nExtent>=m_nLongestExtent)
	{
		// 获取列表框最大长度
		m_nLongestExtent = 0;
		for (int i = 0; i<lResult; i++)
		{
			if (m_arrExtents[i]>m_nLongestExtent)
				m_nLongestExtent = m_arrExtents[i];
		}
	}
	SetHorizontalExtent(m_nLongestExtent);

	return lResult;
}

//****************************************************************************
// Function:
//
//     CHListBox::OnSetTabStops()
//
// Purpose:
//
//     Intercepts the LB_SETTABSTOPS message to update tab stop array
//
// History:
//
//   Date   Comment                                           Initials
// ======== ================================================= ========
//  1/31/96 Created                                             JMR
//****************************************************************************
LRESULT CHListBox::OnSetTabStops(WPARAM wParam, LPARAM lParam)
{
	LRESULT lResult = Default();
	if (!lResult)
		return lResult;

	m_nTabStops = wParam;
	if (NULL != m_lpTabStops)
	{
		delete []m_lpTabStops;
		m_lpTabStops = NULL;
	}
	
	if (m_nTabStops>0)
	{
		m_lpTabStops = new int[m_nTabStops];
		memcpy(m_lpTabStops, (void*)lParam, m_nTabStops*sizeof(int));

		CDC* pDC = GetDC();
		HFONT hFont = (HFONT)SendMessage(WM_GETFONT);
		CFont *pFont = CFont::FromHandle(hFont);
		ASSERT (pFont);
		CFont* pPrevFont = pDC->SelectObject(pFont);
		CSize size;

		GetTextExtentPoint32(pDC->GetSafeHdc(), 
			_T("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"), 
			52, &size);

		pDC->SelectObject(pPrevFont);
		ReleaseDC(pDC);

		int aveCharWidth = (size.cx/26+1)/2;

		for (int i=0; i<m_nTabStops; i++)
			m_lpTabStops[i] = (m_lpTabStops[i]*aveCharWidth+2)/4;
	}
	if (!m_bLocked)
		UpdateHExtent();

	return lResult;
}