xbrowseforfolder.cpp

这个则是一个简单的监视文件系统的例子

// XBrowseForFolder.cpp  Version 1.0
//
// Author:  Hans Dietrich
//          [e-mail]
//
// Description:
//     XBrowseForFolder.cpp implements XBrowseForFolder(), a function that
//     wraps SHBrowseForFolder().
//
// History
//     Version 1.0 - 2003 September 25
//     - Initial public release
//
// This software is released into the public domain.  You are free to use it 
// in any way you like.
//
// This software is provided "as is" with no expressed or implied warranty.  
// I accept no liability for any damage or loss of business that this software 
// may cause.
//
///////////////////////////////////////////////////////////////////////////////

// if you don't want to use MFC, comment out the following line:
#include "stdafx.h"

#ifndef __AFX_H__
#include "windows.h"
#include "crtdbg.h"
#include "tchar.h"
#endif

#include "Shlobj.h"
#include "io.h"
#include "XBrowseForFolder.h"

#pragma warning(disable: 4127)	// conditional expression is constant (_ASSERTE)


#ifndef __AFX_H__

#define TRACE (void(0))

///////////////////////////////////////////////////////////////////////////////
// CRect - a minimal CRect class

class CRect : public tagRECT
{
public:
	CRect() { }
	CRect(int l, int t, int r, int b) { left = l; 
										top = t; 
										right = r; 
										bottom = b; }
	int Width() const { return right - left; }
	int Height() const { return bottom - top; }
	void SwapLeftRight() { SwapLeftRight(LPRECT(this)); }
	static void SwapLeftRight(LPRECT lpRect) { LONG temp = lpRect->left; 
											   lpRect->left = lpRect->right; 
											   lpRect->right = temp; }
	operator LPRECT() { return this; }
};
#endif


///////////////////////////////////////////////////////////////////////////////
// ScreenToClientX - helper function in case non-MFC
static void ScreenToClientX(HWND hWnd, LPRECT lpRect)
{
	_ASSERTE(::IsWindow(hWnd));
	::ScreenToClient(hWnd, (LPPOINT)lpRect);
	::ScreenToClient(hWnd, ((LPPOINT)lpRect)+1);
}

///////////////////////////////////////////////////////////////////////////////
// MoveWindowX - helper function in case non-MFC
static void MoveWindowX(HWND hWnd, CRect& rect, BOOL bRepaint)
{
	_ASSERTE(::IsWindow(hWnd));
	::MoveWindow(hWnd, rect.left, rect.top,
		rect.Width(), rect.Height(), bRepaint);
}

///////////////////////////////////////////////////////////////////////////////
// BrowseCallbackProc - SHBrowseForFolder callback function
static int CALLBACK BrowseCallbackProc(HWND hwnd,		// Window handle to the browse dialog box
									   UINT uMsg,		// Value identifying the event
									   LPARAM lParam,	// Value dependent upon the message 
									   LPARAM lpData)	// Application-defined value that was 
														// specified in the lParam member of the 
														// BROWSEINFO structure
{
	switch (uMsg)
	{
		case BFFM_INITIALIZED:		// sent when the browse dialog box has finished initializing. 
		{
			// remove context help button from dialog caption
			LONG lStyle = ::GetWindowLong(hwnd, GWL_STYLE);
			lStyle &= ~DS_CONTEXTHELP;
			::SetWindowLong(hwnd, GWL_STYLE, lStyle);
			lStyle = ::GetWindowLong(hwnd, GWL_EXSTYLE);
			lStyle &= ~WS_EX_CONTEXTHELP;
			::SetWindowLong(hwnd, GWL_EXSTYLE, lStyle);

			// set initial directory
			::SendMessage(hwnd, BFFM_SETSELECTION, TRUE, lpData);

			// find the folder tree and make dialog larger
			HWND hwndTree = FindWindowEx(hwnd, NULL, _T("SysTreeView32"), NULL);
			if (hwndTree)
			{
				// make the dialog larger
				CRect rectDlg;
				::GetWindowRect(hwnd, &rectDlg);
				rectDlg.right += 40;
				rectDlg.bottom += 30;
				MoveWindowX(hwnd, rectDlg, TRUE);
				::GetClientRect(hwnd, &rectDlg);

				// move the Cancel button
				CRect rectCancel(0, 0, 0, 0);
				HWND hwndCancel = ::GetDlgItem(hwnd, IDCANCEL);
				if (hwndCancel)
					::GetWindowRect(hwndCancel, &rectCancel);
				ScreenToClientX(hwnd, &rectCancel);
				int h = rectCancel.Height();
				int w = rectCancel.Width();
				rectCancel.bottom = rectDlg.bottom - 5;
				rectCancel.top = rectCancel.bottom - h;
				rectCancel.right = rectDlg.right - 5;
				rectCancel.left = rectCancel.right - w;
				if (hwndCancel)
					MoveWindowX(hwndCancel, rectCancel, FALSE);

				// move the OK button
				CRect rectOK(0, 0, 0, 0);
				HWND hwndOK = ::GetDlgItem(hwnd, IDOK);
				if (hwndOK)
					::GetWindowRect(hwndOK, &rectOK);
				ScreenToClientX(hwnd, &rectOK);
				rectOK.bottom = rectDlg.bottom - 5;
				rectOK.top = rectOK.bottom - h;
				rectOK.right = rectCancel.left - 10;
				rectOK.left = rectOK.right - w;
				if (hwndOK)
					MoveWindowX(hwndOK, rectOK, FALSE);

				// expand the folder tree to fill the dialog
				CRect rectTree;
				::GetWindowRect(hwndTree, &rectTree);
				ScreenToClientX(hwnd, &rectTree);
				rectTree.top = 5;
				rectTree.left= 5;
				rectTree.bottom = rectOK.top - 5;
				rectTree.right = rectDlg.right - 5;
				MoveWindowX(hwndTree, rectTree, FALSE);
			}
			else
			{
				TRACE(_T("ERROR - tree control not found.\n"));
				_ASSERTE(hwndTree);
			}
		}
		break;

		case BFFM_SELCHANGED:		// sent when the selection has changed
		{
			TCHAR szDir[MAX_PATH*2] = { 0 };

			// fail if non-filesystem
			BOOL bRet = SHGetPathFromIDList((LPITEMIDLIST) lParam, szDir);
			if (bRet)
			{
				// fail if folder not accessible
				if (_taccess(szDir, 00) != 0)
				{
					bRet = FALSE;
				}
				else
				{
					SHFILEINFO sfi;
					::SHGetFileInfo((LPCTSTR)lParam, 0, &sfi, sizeof(sfi), 
							SHGFI_PIDL | SHGFI_ATTRIBUTES);
					TRACE(_T("dwAttributes=0x%08X\n"), sfi.dwAttributes);

					// fail if pidl is a link
					if (sfi.dwAttributes & SFGAO_LINK)
					{
						TRACE(_T("SFGAO_LINK\n"));
						bRet = FALSE;
					}
				}
			}

			// if invalid selection, disable the OK button
			if (!bRet)
			{
				::EnableWindow(GetDlgItem(hwnd, IDOK), FALSE);
			}

			TRACE(_T("szDir=%s\n"), szDir);
		}
		break;
	}
         
	return 0;
}

///////////////////////////////////////////////////////////////////////////////
//
// XBrowseForFolder()
//
// Purpose:     Invoke the SHBrowseForFolder API.  If lpszInitialFolder is
//              supplied, it will be the folder initially selected in the tree 
//              folder list.  Otherwise, the initial folder will be set to the 
//              current directory.  The selected folder will be returned in 
//              lpszBuf.
//
// Parameters:  hWnd              - handle to the owner window for the dialog
//              lpszInitialFolder - initial folder in tree;  if NULL, the initial
//                                  folder will be the current directory.
//              lpszBuf           - buffer for the returned folder path
//              dwBufSize         - size of lpszBuf in TCHARs
//
// Returns:     BOOL - TRUE = success;  FALSE = user hit Cancel
//
BOOL XBrowseForFolder(HWND hWnd,
					  LPCTSTR lpszInitialFolder,
					  LPTSTR lpszBuf,
					  DWORD dwBufSize)
{
	_ASSERTE(lpszBuf);
	_ASSERTE(dwBufSize >= MAX_PATH);

	if (lpszBuf == NULL || dwBufSize < MAX_PATH)
		return FALSE;

	lpszBuf[0] = _T('\0');

	TCHAR szInitialPath[MAX_PATH*2];
	ZeroMemory(szInitialPath, sizeof(szInitialPath));

	if (lpszInitialFolder && lpszInitialFolder[0] != _T('\0'))
	{
		_tcsncpy(szInitialPath, lpszInitialFolder, 
					sizeof(szInitialPath)/sizeof(TCHAR)-2);
	}
	else
	{
		// no initial folder, set to current directory
		::GetCurrentDirectory(sizeof(szInitialPath)/sizeof(TCHAR)-2, 
				szInitialPath);
	}

	BROWSEINFO bi;
	ZeroMemory(&bi, sizeof(BROWSEINFO));

	bi.hwndOwner = hWnd;
	bi.ulFlags   = BIF_RETURNONLYFSDIRS;	// do NOT use BIF_NEWDIALOGSTYLE, 
											// BIF_EDITBOX, or BIF_STATUSTEXT
	bi.lpfn      = BrowseCallbackProc;
	bi.lParam    = (LPARAM) szInitialPath;

	LPITEMIDLIST pidl = SHBrowseForFolder(&bi);

	BOOL bRet = FALSE;

	if (pidl)
	{
		TCHAR szBuffer[MAX_PATH*2];
		szBuffer[0] = _T('\0');

		if (SHGetPathFromIDList(pidl, szBuffer))
		{
			ZeroMemory(lpszBuf, dwBufSize);
			_tcsncpy(lpszBuf, szBuffer, dwBufSize-1);
			bRet = TRUE;
		}
		else
		{
			TRACE(_T("SHGetPathFromIDList failed\n"));
		}

		IMalloc *pMalloc = NULL; 
		if (SUCCEEDED(SHGetMalloc(&pMalloc)) && pMalloc) 
		{  
			pMalloc->Free(pidl);  
			pMalloc->Release(); 
		}
	}

	return bRet;
}