SHBrowseForFolder设置初始目录中CALLBACK函数的使用

目的：
通过BROWSEINFO，SHBrowseForFolder打开Directory对话框，并且通过int CALLBACK BrowseCallbackProc()设置初始目录.

(源代码)打开目录选择对话框：

void CUnpackView::OnButtonPath(CDataExchange* pDX)
{

// TODO: Add your control notification handler code here
char dispname[MAX_PATH];
char copytopath[MAX_PATH];


BROWSEINFO bi;
ITEMIDLIST *pidl;

bi.hwndOwner = 0;
bi.pidlRoot = 0; //set the default browser path
bi.pszDisplayName = dispname;
bi.lpszTitle = "Verzeichniss auswählen";
bi.ulFlags = BIF_STATUSTEXT;//BIF_RETURNONLYFSDIRS;
bi.lpfn = BrowseCallbackProc; //调用回调函数
bi.lParam = 0;
bi.iImage = 0;



if ((pidl = SHBrowseForFolder(&bi))!=NULL) //
{

memset(copytopath, 0, MAX_PATH);
SHGetPathFromIDList(pidl, copytopath);//copytopath
//
sourceDir = (CString) copytopath;

}
//OnInitialUpdate();
UpdateData(false);
Invalidate();

if ( plc.checkFolder((LPCTSTR)sourceDir) )
{

openedSourceDir = (LPCTSTR)sourceDir;

//--get the LastWriteTime of folder/files
WIN32_FIND_DATA ffd ;
HANDLE hFind = FindFirstFile(openedSourceDir,&ffd);
SYSTEMTIME stUTC, stLocal;
FileTimeToSystemTime(&(ffd.ftLastWriteTime), &stUTC);
SystemTimeToTzSpecificLocalTime(NULL, &stUTC, &stLocal);
myTime.Format("%d. %d %d, %d:%d", stLocal.wDay,stLocal.wMonth,stLocal.wYear,stLocal.wHour,stLocal.wMinute);
//--
d_ColorStatic.SetWindowText((LPCTSTR)myTime);


GetDlgItem(IDC_BUTTON_ROLLBACK)->EnableWindow(true);
GetDlgItem(IDC_BUTTON_REPORT)->EnableWindow(true);
GetDlgItem(IDC_STATIC_STATUSTITLE)->EnableWindow(false);

}
else
{

GetDlgItem(IDC_BUTTON_ROLLBACK)->EnableWindow(false);
GetDlgItem(IDC_BUTTON_REPORT)->EnableWindow(false);
GetDlgItem(IDC_STATIC_STATUSTITLE)->EnableWindow(false);
AfxMessageBox("Die angegebene Verzeichniss ist nicht richtig, bitte versuchen Sie nochmal.");

}

}

(源代码)CALLBACK函数：
在.h中：

CString sicherungDir;
static int CALLBACK BrowseCallbackProc(HWND hwnd, UINT uMsg, LPARAM lParam, LPARAM lpData);

在.cpp中：

int CALLBACK CUnpackView::BrowseCallbackProc(HWND hwnd, UINT uMsg, LPARAM lParam, LPARAM lpData)
{

//CALLBACKSTRUCT * cs = (CALLBACKSTRUCT*) lpData;

CString dir(_T(""));
BOOL hasInitial = false;
// * Statische Member-Funktionen haben keinen this-Zeiger: *
// * this does not work, because the pUnpack is a new obj,
// * pUnpack->openedSourceDir is the new one

//---- use the View pointobject
CMDIFrameWnd *pFrame = (CMDIFrameWnd*)AfxGetApp()->m_pMainWnd;
CMDIChildWnd *pChild = (CMDIChildWnd *) pFrame->GetActiveFrame();
CUnpackView *pView = (CUnpackView *) pChild->GetActiveView();
//--

if ( pView->openedSourceDir != "")

dir = pView->openedSourceDir; // the default stays at the opened folder failed!because pView is a new pObject

else

dir = CPublic::sSicherungDir; //if first time to open the folder dialog

/////////////////////////////////////////////////
//'d:\\' can not be recognised by SHGetPathFromIDList()
// must be changed into 'd:\'
/////////////////////////////////////////////////
dir.Replace("\\\\","\\");

switch(uMsg)
{

case BFFM_INITIALIZED: //initial

hasInitial =true;
::SendMessage(hwnd,BFFM_SETSELECTION,TRUE,(LPARAM)(LPCTSTR)dir ); //"d:\\datenversicherung"
//AfxMessageBox("BFFM_INITIALIZED");

break;

case BFFM_SELCHANGED: //path changed
{

/////////////////////////////////////////////
// to avoid SHGetPathFromIDList()twice running
// before "case BFFM_INITIALIZED" has been done
////////////////////////////////////////////
if (hasInitial)
{

char curr[MAX_PATH];

SHGetPathFromIDList((LPCITEMIDLIST)lParam,curr);

CString s;
s.Format("BFFM_SELCHANGED, curr: %s",curr);
AfxMessageBox(s);

if(curr[strlen(curr)-1]==92)
sprintf(curr,"%s",curr);
else
sprintf(curr,"%s\\",curr);

::SendMessage(hwnd,BFFM_SETSTATUSTEXT,0,(LPARAM)curr);

}

}
break;

}
return 0;

}

注意：
在对CALLBACK函数的使用中，必须是类的静态成员函数。
否则，用MS编译器，会得到这个编译错误：

error C2664: 'Bubblesort' : cannot convert parameter 4 from 'int (__stdcall CCallbackTester::*)(const unsigned char *,const unsigned char *)' to 'int (__stdcall *)(const unsigned char *,const unsigned char *)' There is no context in which this conversion is possible

参考：
Visual C++中回调函数使用的变身大法
回调函数指南（Callback Functions Tutorial）
How to Implement Callbacks in C and C++