常用的代码片断

1、选择文件夹

 （1） 封装了一个类，DirDialog.h为：

// DirDialog.h: interface for the CDirDialog class.

//

//

#if !defined(AFX_DIRDIALOG_H__62FFAC92_1DEE_11D1_B87A_0060979CDF6D__INCLUDED_)

#define AFX_DIRDIALOG_H__62FFAC92_1DEE_11D1_B87A_0060979CDF6D__INCLUDED_

#if _MSC_VER >= 1000

#pragma once

#endif // _MSC_VER >= 1000

class 选择目录的对话框类

class  CDirDialog

{

public:

 brief 构造函数

 CDirDialog();

 brief 析构函数

 virtual ~CDirDialog();

 brief 弹出系统对话框 取得的路径名

 param CWnd *pParent 父窗口对象指针

 return 成功true,失败false

 bool DoBrowse(CWnd *pParent);

 brief dialog的标题

 CString m_strDlgTitle;

 brief 最终选择的目录

 CString m_strSelDir;  

 brief 初始化的根目录

 CString m_strRootDir; 

 brief 初始化选择的目录

 CString m_strInitDir; 

 brief 在目录列表上方显示的标题

 CString m_strTitle;   

 brief 当选择目录时，是否可以显示选择的目录

 bool m_bStatus;       

 brief 选择成功后 和改目录链接的Image的索引，它是系统 image list的索引

 int  m_iImageIndex;   

protected:

 brief 控制一个目录是否可以选择，并且返回状态信息

 param LPCSTR lpcsSelection 当前选择的目录

 param CString& csStatusText 返回的状态信息

 return  可以选择true, 不可以选择false

 virtual bool SelChanged(LPCSTR lpcsSelection, CString& csStatusText);

 brief 选择目录的回调函数

 static int __stdcall BrowseCtrlCallback(HWND hwnd, UINT uMsg, LPARAM lParam, LPARAM lpData);

};

#endif // !defined(AFX_DIRDIALOG_H__62FFAC92_1DEE_11D1_B87A_0060979CDF6D__INCLUDED_)

（2）DirDialog.cpp文件为：

///

// DirDialog.cpp: implementation of the CDirDialog class.

//

//

#include "stdafx.h"

#include "DirDialog.h"

#include "shlobj.h"

#ifdef _DEBUG

#undef THIS_FILE

static char THIS_FILE[]=__FILE__;

#define new DEBUG_NEW

#endif

int __stdcall CDirDialog::BrowseCtrlCallback(HWND hwnd, UINT uMsg, LPARAM lParam, LPARAM lpData)

{

 CDirDialog* pDirDialogObj = (CDirDialog*)lpData;

 if (uMsg == BFFM_INITIALIZED )

 {

  if( ! pDirDialogObj->m_strInitDir.IsEmpty() )

   ::SendMessage(hwnd, BFFM_SETSELECTION, TRUE, (LPARAM)(LPCTSTR)(pDirDialogObj->m_strInitDir));

  if( ! pDirDialogObj->m_strDlgTitle.IsEmpty() )

   ::SetWindowText(hwnd, (LPCTSTR) pDirDialogObj->m_strDlgTitle);

 }

 else if( uMsg == BFFM_SELCHANGED )

 {

  LPITEMIDLIST pidl = (LPITEMIDLIST) lParam;

  char selection[MAX_PATH];

  if( ! ::SHGetPathFromIDList(pidl, selection) )

   selection[0] = _T('/0');

  CString csStatusText;

  bool bOK = pDirDialogObj->SelChanged(selection, csStatusText);

  if( pDirDialogObj->m_bStatus )

   ::SendMessage(hwnd, BFFM_SETSTATUSTEXT , 0, (LPARAM)(LPCSTR)csStatusText);

  BOOL bCanSelect = TRUE ;

  if(!bOK)

   bCanSelect = FALSE ;

  ::SendMessage(hwnd, BFFM_ENABLEOK, 0, bCanSelect);

 }

 return 0;

}

//

// Construction/Destruction

//

CDirDialog::CDirDialog()

{

 m_bStatus = false ;

}

CDirDialog::~CDirDialog()

{

}

//取得的路径名有路径标识符

bool CDirDialog::DoBrowse(CWnd *pParent)

{

 m_strInitDir.TrimRight();

 if( ! m_strInitDir.IsEmpty() )

 {

  if( m_strInitDir.Right(1) == _T("//") || m_strInitDir.Right(1) == _T("//") )

   m_strInitDir = m_strInitDir.Left(m_strInitDir.GetLength() - 1);

  //correct selection "X:"

  if( m_strInitDir.Right(1) == _T(":"))

   m_strInitDir+=_T("//");

 }

 bool bOK = false ;

 LPMALLOC pMalloc;

 if (SHGetMalloc (&pMalloc)!= NOERROR)

 {

  return bOK;

 }

 BROWSEINFO bInfo;

 LPITEMIDLIST pidl;

 ZeroMemory ( (PVOID) &bInfo,sizeof (BROWSEINFO));

 if (!m_strRootDir.IsEmpty ())

 {

  OLECHAR       olePath[MAX_PATH];

  ULONG         chEaten;

  ULONG         dwAttributes;

  HRESULT       hr;

  LPSHELLFOLDER pDesktopFolder;

  //

  // Get a pointer to the Desktop's IShellFolder interface.

  //

  if (SUCCEEDED(SHGetDesktopFolder(&pDesktopFolder)))

  {

   //

   // IShellFolder::ParseDisplayName requires the file name be in Unicode.

   //

#ifndef _UNICODE

   MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, m_strRootDir.GetBuffer(MAX_PATH), -1,

    olePath, MAX_PATH);

#else

   memcpy(olePath,m_strRootDir,m_strRootDir.GetLength() * sizeof(TCHAR));

#endif

   m_strRootDir.ReleaseBuffer (-1);

   //

   // Convert the path to an ITEMIDLIST.

   //

   hr = pDesktopFolder->ParseDisplayName(NULL,

    NULL,

    olePath,

    &chEaten,

    &pidl,

    &dwAttributes);

   if (FAILED(hr))

   {

    pMalloc ->Free (pidl);

    pMalloc ->Release ();

    return bOK;

   }

   bInfo.pidlRoot = pidl;

  }

 }

 if(m_strTitle.IsEmpty())

  m_strTitle = _T("请选择目录");

 bInfo.hwndOwner = pParent->GetSafeHwnd() ;

 bInfo.pszDisplayName = m_strSelDir.GetBuffer (MAX_PATH);

 bInfo.lpszTitle = (LPCTSTR)m_strTitle;

 bInfo.ulFlags = BIF_RETURNFSANCESTORS|BIF_RETURNONLYFSDIRS| (m_bStatus ? BIF_STATUSTEXT : 0);

 bInfo.lpfn = BrowseCtrlCallback;  // address of callback function

 bInfo.lParam = (LPARAM)this;      // pass address of object to callback function

 if ((pidl = ::SHBrowseForFolder(&bInfo)) == NULL)

 {

  m_strSelDir.ReleaseBuffer();

  return bOK;

 }

 m_strSelDir.ReleaseBuffer();

 m_iImageIndex = bInfo.iImage;

 bOK = (::SHGetPathFromIDList(pidl,m_strSelDir.GetBuffer(MAX_PATH)) == TRUE );

 m_strSelDir.ReleaseBuffer();

 pMalloc ->Free(pidl);

 pMalloc ->Release();

 if(bOK)

 {

  if(m_strSelDir.IsEmpty())

   m_strSelDir = _T('//');

  else if(m_strSelDir.Right(1) != _T('//') )

   m_strSelDir += _T('//');

 }

 return bOK;

}

bool CDirDialog::SelChanged(LPCSTR lpcsSelection, CString& csStatusText)

{

 bool bOK = false ;

 csStatusText.Empty();

 CString strPath(lpcsSelection);

 if(!strPath.IsEmpty())

 {

  if(m_bStatus)

   csStatusText = strPath ;

  bOK = true;

 }

 return bOK;

}

（3）在主函数中调用

 UpdateData(true);

 CDirDialog dlg;

 if(dlg.DoBrowse(this))

 {

  m_strFloderPath = dlg.m_strSelDir;      //获得选中的文件夹路径

  UpdateData(FALSE);

 }