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A better front end to WinDiff

, 18 Oct 2000
A GUI front end to a handy utility
runwindiff.zip
runwindiff_src.zip
RunWinDiff_src
res
32x32x256_Browse.ico
32x32x256_Cancel.ico
32x32x256_File.ico
32x32x256_Ok.ico
close.ico
file_ope.ico
help_off.ico
help_on.ico
idr_comp.ico
open.ico
windiff.ico
RunWinDiff.clw
RunWinDiff.dsp
RunWinDiff.dsp.VC5
RunWinDiff.dsw
Release
RunWinDiff.exe
// DropComboBox.cpp : implementation file
//
// Autocompleting combo-box (like the URL edit box in netscape)
// that accepts dropped files
//
// Written by Chris Maunder (cmaunder@mail.com)
// Copyright (c) 1998.
//
//	Drop edit stuff taken from "CDropEdit"
//	Copyright 1997 Chris Losinger
//
//	shortcut expansion code modified from :
//	CShortcut, 1996 Rob Warner
//
// This code may be used in compiled form in any way you desire. This
// file may be redistributed unmodified by any means PROVIDING it is 
// not sold for profit without the authors written consent, and 
// providing that this notice and the authors name is included. If 
// the source code in  this file is used in any commercial application 
// then acknowledgement must be made to the author of this file 
// (in whatever form you wish).
//
// This file is provided "as is" with no expressed or implied warranty.
// The author accepts no liability if it causes any damage whatsoever.
//
// Expect bugs.
// 
// Please use and enjoy. Please let me know of any bugs/mods/improvements 
// that you have found/implemented and I will fix/incorporate them into this
// file. 
//
// Modified: 12 Sep 1998 Setting correct cursor position after 
//                       auto-complete: Petr Stejskal and Ryan Schneider
//
/////////////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "DropComboBox.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <afxdisp.h>

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

/////////////////////////////////////////////////////////////////////////////
// CDropComboBox

CDropComboBox::CDropComboBox()
{
	m_bAutoComplete = TRUE;
	m_bAllowFiles   = TRUE;
    m_bAllowDirs    = TRUE;
    m_nMaxFiles     = 10;
    m_bNoRepeats    = TRUE;

    // Initialize OLE libraries
	m_bMustUninitOLE = FALSE;
    _AFX_THREAD_STATE* pState = AfxGetThreadState();
    if (!pState->m_bNeedTerm)
	{
		SCODE sc = ::OleInitialize(NULL);
		if (FAILED(sc))
            AfxMessageBox(_T("OLE initialization failed. Make sure that the OLE libraries are the correct version"));
		else
			m_bMustUninitOLE = TRUE;
	}
}

CDropComboBox::~CDropComboBox()
{
	// Uninitialize OLE support
	if (m_bMustUninitOLE)
		::OleUninitialize();
}


BEGIN_MESSAGE_MAP(CDropComboBox, CComboBox)
	//{{AFX_MSG_MAP(CDropComboBox)
	ON_CONTROL_REFLECT(CBN_EDITUPDATE, OnEditUpdate)
    ON_MESSAGE(CB_ADDSTRING, OnAddString)
    ON_MESSAGE(CB_INSERTSTRING, OnInsertString)
	ON_WM_CREATE()
	ON_WM_DROPFILES()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CDropComboBox message handlers

BOOL CDropComboBox::PreTranslateMessage(MSG* pMsg)
{
	// Need to check for backspace/delete. These will modify the text in
	// the edit box, causing the auto complete to just add back the text
	// the user has just tried to delete. 

	if (pMsg->message == WM_KEYDOWN)
	{
		m_bAutoComplete = TRUE;

		int nVirtKey = (int) pMsg->wParam;
		if (nVirtKey == VK_DELETE || nVirtKey == VK_BACK)
			m_bAutoComplete = FALSE;
	}

	return CComboBox::PreTranslateMessage(pMsg);
}

LONG CDropComboBox::OnAddString(UINT /*wParam*/, LONG lParam)
{
    LPCTSTR lpszText = (LPCTSTR)lParam;

    int nIndex = CheckRepeats(lpszText);
    if (nIndex != CB_ERR)
        return nIndex;

    CheckOverflow();

    LONG lResult = Default();

    RecalcDropWidth();

    return lResult;
}

LONG CDropComboBox::OnInsertString(UINT /*wParam*/, LONG lParam)
{
    LPCTSTR lpszText = (LPCTSTR)lParam;

    int nIndex = CheckRepeats(lpszText);
    if (nIndex != CB_ERR)
        return nIndex;

    CheckOverflow();

    LONG lResult = Default();

    RecalcDropWidth();

    return lResult;
}

void CDropComboBox::OnEditUpdate() 
{
  // if we are not to auto update the text, get outta here
  if (!m_bAutoComplete) 
      return;

  // Get the text in the edit box
  CString str;
  GetWindowText(str);
  int nLength = str.GetLength();
  
  // Currently selected range
  DWORD dwCurSel = GetEditSel();
  WORD dStart = LOWORD(dwCurSel);
  WORD dEnd   = HIWORD(dwCurSel);

  // Search for, and select in, and string in the combo box that is prefixed
  // by the text in the edit box
  if (SelectString(-1, str) == CB_ERR)
  {
      SetWindowText(str);		// No text selected, so restore what was there before
      if (dwCurSel != CB_ERR)
        SetEditSel(dStart, dEnd);	//restore cursor postion
  }

  // Set the text selection as the additional text that we have added
  if (dEnd < nLength && dwCurSel != CB_ERR)
      SetEditSel(dStart, dEnd);
  else
      SetEditSel(nLength, -1);
}

int CDropComboBox::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
	if (CComboBox::OnCreate(lpCreateStruct) == -1)
		return -1;
	
	DragAcceptFiles(TRUE);
	
	return 0;
}


//	handle WM_DROPFILES
//

void CDropComboBox::OnDropFiles(HDROP dropInfo)
{
	// Get the number of pathnames that have been dropped
	WORD wNumFilesDropped = DragQueryFile(dropInfo, -1, NULL, 0);

	CString firstFile="";

	// get all file names. but we'll only need the first one.
	for (WORD x = 0 ; x < wNumFilesDropped; x++) {

		// Get the number of bytes required by the file's full pathname
		WORD wPathnameSize = DragQueryFile(dropInfo, x, NULL, 0);

		// Allocate memory to contain full pathname & zero byte
		char * npszFile = (char *) LocalAlloc(LPTR, wPathnameSize += 1);

		// If not enough memory, skip this one
		if (npszFile == NULL) continue;

		// Copy the pathname into the buffer
		DragQueryFile(dropInfo, x, npszFile, wPathnameSize);

		// we only care about the first
		if (firstFile=="")
			firstFile=npszFile;

		// clean up
		LocalFree(npszFile);
	}

	// Free the memory block containing the dropped-file information
	DragFinish(dropInfo);

	// if this was a shortcut, we need to expand it to the target path
	CString expandedFile = ExpandShortcut(firstFile);

	// if that worked, we should have a real file name
	if (expandedFile!="") 
		firstFile=expandedFile;

	
	struct _stat buf;
	// get some info about that file
	int result = _stat( firstFile, &buf );
	if( result == 0 ) {

		// verify that we have a dir (if we want dirs)
		if ((buf.st_mode & _S_IFDIR) == _S_IFDIR) 
        {
			if (m_bAllowDirs)
				SetWindowText(firstFile);
            SetEditSel(firstFile.GetLength(), firstFile.GetLength());
		} 
		// verify that we have a file (if we want files)
        else if ((buf.st_mode & _S_IFREG) == _S_IFREG) 
        {
			if (m_bAllowFiles)
				SetWindowText(firstFile);
            SetEditSel(firstFile.GetLength(), firstFile.GetLength());
		}
	}
}

/////////////////////////////////////////////////////////////////////////////
// CDropComboBox public functions

// inserts string at the top of the list of strings
void CDropComboBox::PushString(LPCTSTR szText)
{
    CString str;
    CStringArray aStrings;
    aStrings.Add(szText);

    int nNumStrings = GetCount();
    for (int i = 0; i < nNumStrings; i++)
    {
        GetLBText(i, str);
        if (m_bNoRepeats && str != szText)
            aStrings.Add(str);
    }
    ResetContent();
    nNumStrings = min(aStrings.GetSize(), m_nMaxFiles);

    for (i = 0; i < nNumStrings; i++)
    {
        AddString(aStrings[i]);
    }
}


/////////////////////////////////////////////////////////////////////////////
// CDropComboBox implementation

//////////////////////////////////////////////////////////////////
//	use IShellLink to expand the shortcut
//	returns the expanded file, or "" on error
//
//	original code was part of CShortcut 
//	1996 by Rob Warner
//	rhwarner@southeast.net
//	http://users.southeast.net/~rhwarner

CString CDropComboBox::ExpandShortcut(CString &inFile)
{
	CString outFile = "";

    // Make sure we have a path
    ASSERT(inFile != _T(""));

    IShellLink* psl;
    HRESULT hres;
    LPTSTR lpsz = inFile.GetBuffer(MAX_PATH);

    // Create instance for shell link
    hres = ::CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER,
        IID_IShellLink, (LPVOID*) &psl);
    if (SUCCEEDED(hres))
    {
        // Get a pointer to the persist file interface
        IPersistFile* ppf;
        hres = psl->QueryInterface(IID_IPersistFile, (LPVOID*) &ppf);
        if (SUCCEEDED(hres))
        {
            // Make sure it's ANSI
            WORD wsz[MAX_PATH];
            ::MultiByteToWideChar(CP_ACP, 0, lpsz, -1, wsz, MAX_PATH);

            // Load shortcut
            hres = ppf->Load(wsz, STGM_READ);
            if (SUCCEEDED(hres)) {
				WIN32_FIND_DATA wfd;
				// find the path from that
				HRESULT hres = psl->GetPath(outFile.GetBuffer(MAX_PATH), 
								MAX_PATH,
								&wfd, 
								SLGP_UNCPRIORITY);

				outFile.ReleaseBuffer();
            }
            ppf->Release();
        }
        psl->Release();
    }

	inFile.ReleaseBuffer();

	// if this fails, outFile == ""
    return outFile;
}

LONG CDropComboBox::CheckRepeats(LPCTSTR lpszText)
{
    if (!m_bNoRepeats)
        return CB_ERR;

    return FindString(-1, lpszText);
}

void CDropComboBox::CheckOverflow()
{
    if (m_nMaxFiles > 0 && GetCount() >= m_nMaxFiles)
        DeleteString(m_nMaxFiles-1);
}

void CDropComboBox::RecalcDropWidth()
{
    // Reset the dropped width
    int nNumEntries = GetCount();
    int nWidth = 0;
    CString str;

    CClientDC dc(this);
    int nSave = dc.SaveDC();
    dc.SelectObject(GetFont());

    int nScrollWidth = ::GetSystemMetrics(SM_CXVSCROLL);
    for (int i = 0; i < nNumEntries; i++)
    {
        GetLBText(i, str);
        int nLength = dc.GetTextExtent(str).cx + nScrollWidth;
        nWidth = max(nWidth, nLength);
    }

    dc.RestoreDC(nSave);
    SetDroppedWidth(nWidth);
}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Chris Maunder
Founder CodeProject
Canada Canada
Chris is the Co-founder, Administrator, Architect, Chief Editor and Shameless Hack who wrote and runs The Code Project. He's been programming since 1988 while pretending to be, in various guises, an astrophysicist, mathematician, physicist, hydrologist, geomorphologist, defence intelligence researcher and then, when all that got a bit rough on the nerves, a web developer. He is a Microsoft Visual C++ MVP both globally and for Canada locally.
 
His programming experience includes C/C++, C#, SQL, MFC, ASP, ASP.NET, and far, far too much FORTRAN. He has worked on PocketPCs, AIX mainframes, Sun workstations, and a CRAY YMP C90 behemoth but finds notebooks take up less desk space.
 
He dodges, he weaves, and he never gets enough sleep. He is kind to small animals.
 
Chris was born and bred in Australia but splits his time between Toronto and Melbourne, depending on the weather. For relaxation he is into road cycling, snowboarding, rock climbing, and storm chasing.
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