文件夹浏览(SHBrowseForFolder)

from http://www.cnblogs.com/Clingingboy/archive/2011/04/16/2018284.html

一.首先要为SHBrowseForFolder准备一个结构体BROWSEINFO

typedef struct _browseinfoW {
    HWND        hwndOwner;
    PCIDLIST_ABSOLUTE pidlRoot;
    LPWSTR       pszDisplayName;        // Return display name of item selected.
    LPCWSTR      lpszTitle;                     // text to go in the banner over the tree.
    UINT         ulFlags;                       // Flags that control the return stuff
    BFFCALLBACK  lpfn;
    LPARAM       lParam;                        // extra info that's passed back in callbacks
    int          iImage;                        // output var: where to return the Image index.
} BROWSEINFOW, *PBROWSEINFOW, *LPBROWSEINFOW;

二.获取PIDL

在BROWSEINFOW结构体中,pidlRoot是最关键的,需要调用一些额外的函数来获取PIDL,然后给pidlRoot赋值

1.获取特殊的目录地址

在Windows中有很多特殊的的目录地址,如我的电脑,控件面板,我的图片等,如下定义

#define CSIDL_DESKTOP                   0x0000        // <desktop>
#define CSIDL_INTERNET                  0x0001        // Internet Explorer (icon on desktop)
#define CSIDL_PROGRAMS                  0x0002        // Start Menu\Programs
#define CSIDL_CONTROLS                  0x0003        // My Computer\Control Panel
#define CSIDL_PRINTERS                  0x0004        // My Computer\Printers
#define CSIDL_PERSONAL                  0x0005        // My Documents
#define CSIDL_FAVORITES                 0x0006        // <user name>\Favorites
#define CSIDL_STARTUP                   0x0007        // Start Menu\Programs\Startup
#define CSIDL_RECENT                    0x0008        // <user name>\Recent

我们可以通过SHGetSpecialFolderLocation来填充一个LPITEMIDLIST,

BROWSEINFO bi;
bi.hwndOwner = hDlg;
TCHAR szTitle[MAX_PATH] = {0};
TCHAR szPath[MAX_PATH] = {0};
TCHAR szDisplay[MAX_PATH] = {0};
LPITEMIDLIST pidl = NULL;
SHGetSpecialFolderLocation(NULL, CSIDL_DESKTOP, &pidl);
bi.pidlRoot = pidl;

然后调用SHBrowseForFolder(&bi);就可以出现以下对话框

2.使用IShellFolder获取目录地址

如果不是特殊目录的，可以使用IShellFolder的ParseDisplayName方法,来获取PIDL

首先要调用SHGetDesktopFolder函数来获取IShellFolder,ShellFolder代表桌面,表示是根目录,根目录总是有办法找到任意一个子目录的 
然后调用ParseDisplayName方法来解析目录,最终得到LPITEMIDLIST。 
下面的步骤还是一样把LPITEMIDLIST填充到BROWSEINFO的pidlRoot 字段,调用SHBrowseForFolder方法

SHParseDisplayName方法提供了一个便利

HRESULT SHPathToPIDL(LPCTSTR szPath, LPITEMIDLIST* ppidl)
{
   LPSHELLFOLDER pShellFolder = NULL;
   OLECHAR wszPath[MAX_PATH] = {0};
   ULONG nCharsParsed = 0;

   // Get an IShellFolder interface pointer
   HRESULT hr = SHGetDesktopFolder(&pShellFolder);
   if(FAILED(hr))
      return hr;

   // Convert the path name to Unicode
   MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, szPath, -1, wszPath, MAX_PATH);

   // Call ParseDisplayName() to do the job
   hr = pShellFolder->ParseDisplayName(NULL, NULL, wszPath, &nCharsParsed, ppidl, NULL);

   // Clean up
   pShellFolder->Release();
   return hr;
}

3.获取选择的目录

当选中目录点击确定之后，就需要获取一个文件系统路径,可以使用SHGetPathFromIDList函数

SHGetPathFromIDList(pidlFolder, szPath);

szPath就是我们想要的结果

4.BROWSEINFO的回调方法

在.net中会声明很多的事件,若Initialized,SelectedChanged等,c++是采用消息的机制,根据消息的不同进行不同处理,当然这些消息都是预先定义好的.

#define BFFM_INITIALIZED        1
#define BFFM_SELCHANGED         2
#define BFFM_VALIDATEFAILEDA    3   // lParam:szPath ret:1(cont),0(EndDialog)
#define BFFM_VALIDATEFAILEDW    4   // lParam:wzPath ret:1(cont),0(EndDialog)
#define BFFM_IUNKNOWN           5   // provides IUnknown to client. lParam: IUnknown*

示例如下:

bi.lpfn = BrowseCallbackProc;

int CALLBACK BrowseCallbackProc(HWND hwnd, UINT uMsg, LPARAM lParam, LPARAM dwData)
{
   switch(uMsg)
   {
   case BFFM_INITIALIZED:
      {

      }
      break;

   case BFFM_SELCHANGED:
      {

      }
      break;

   case BFFM_VALIDATEFAILED:

      return 1;
   }

   return 0;
}

三.文件夹选项

如下图,应该是很熟悉

SHGetSettings函数可以获取这些选项的信息,存在结构体SHELLFLAGSTATE当中

typedef struct {
    BOOL fShowAllObjects : 1;
    BOOL fShowExtensions : 1;
    BOOL fNoConfirmRecycle : 1;
    BOOL fShowSysFiles : 1;
    BOOL fShowCompColor : 1;
    BOOL fDoubleClickInWebView : 1;
    BOOL fDesktopHTML : 1;
    BOOL fWin95Classic : 1;
    BOOL fDontPrettyPath : 1;
    BOOL fShowAttribCol : 1;
    BOOL fMapNetDrvBtn : 1;
    BOOL fShowInfoTip : 1;
    BOOL fHideIcons : 1;
#if (NTDDI_VERSION >= NTDDI_VISTA)
    BOOL fAutoCheckSelect: 1;
    BOOL fIconsOnly: 1;
    UINT fRestFlags : 1; // when adding additional flags keep SHELLSTATE and SHGetSettings in sync.

#else
    UINT fRestFlags : 3; // when adding additional flags keep SHELLSTATE and SHGetSettings in sync.
#endif
} SHELLFLAGSTATE, *LPSHELLFLAGSTATE;

必须输入想要获取标识才行,不然就会是默认值(难道是为了性能,为何如此，太麻烦)

SHELLFLAGSTATE sfs;
SHGetSettings(&sfs, SSF_DESKTOPHTML | SSF_SHOWALLOBJECTS |
               SSF_MAPNETDRVBUTTON | SSF_SHOWATTRIBCOL | SSF_SHOWEXTENSIONS);