c++ - 提取所有文件名 - FindFirstFile

Question

我想获取特定目录中所有文件的列表。为此 |我使用以下代码

void GetFileListing(std::list<std::string>& listing, std::string directory, std::string fileFilter, bool recursively=true)
{


//check if directory exits:

     DWORD attribs = ::GetFileAttributesA(directory.c_str());
  if (attribs == INVALID_FILE_ATTRIBUTES || !(attribs & FILE_ATTRIBUTE_DIRECTORY)) {
    return ;
  }

  // If we are going to recurse over all the subdirectories, first of all
  // get all the files that are in this directory that match the filter
  if (recursively)
    GetFileListing(listing, directory, fileFilter, false);

  directory += "\\";

  WIN32_FIND_DATA FindFileData;
  HANDLE hFind = INVALID_HANDLE_VALUE;

  // Setup the filter according to whether we are getting the directories
  // or just the files
  std::string filter = directory + (recursively ? "*" : fileFilter);

  // Find the first file in the directory.
  hFind = FindFirstFile(LPCWSTR(filter.c_str()), &FindFileData);

  if (hFind == INVALID_HANDLE_VALUE)
  {
    DWORD dwError = GetLastError();
    if (dwError!=ERROR_FILE_NOT_FOUND)
    {
      std::cout << "Invalid file handle for filter "<<filter<<". Error is " << GetLastError() << std::endl;
    }
  }
  else
  {
    // Add the first file found to the list
    if (!recursively)
    {
        wstring wFindFileData = FindFileData.cFileName;
      listing.push_back(directory + std::string(wFindFileData.begin(),wFindFileData.end()));
    }

    // List all the other files in the directory.
    while (FindNextFile(hFind, &FindFileData) != 0)
    {
      if (!recursively)
      {
        wstring wFindFileData = FindFileData.cFileName;
        listing.push_back(directory + std::string(wFindFileData.begin(),wFindFileData.end()));
      }
      else
      {
        // If we found a directory then recurse into it
        if ((FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)>0 && FindFileData.cFileName[0]!='.')
        {
            wstring wFindFileData = FindFileData.cFileName;
          GetFileListing(listing, directory + std::string(wFindFileData.begin(),wFindFileData.end()), fileFilter);
        }
      }
    }

    DWORD dwError = GetLastError();
    FindClose(hFind);
    if (dwError != ERROR_NO_MORE_FILES)
    {
      std::cout << "FindNextFile error. Error is "<< dwError << std::endl;
    }
  }
}

int main(int argc, char *argv[])
{
    if(argc < 2)
        return 0;
    std::list<std::string> listing;
    GetFileListing(listing, argv[1], "*");
    for(std::list<std::string>::iterator it = listing.begin(); it!=listing.end();++it)
    {
        std::cout << *it << std::endl;
    }
}

在 args 中，我转移了一个有效的现有目录。实际上 args[1] 变成了“C:\dir”。但我没有得到所需的列表，而是出现以下错误:

Invalid file handle for filter C:\dir\*. Error is 123

我不明白这里有什么问题？

Answer 1

您将 ANSI 与 UNICODE 混合使用，甚至更糟，将 char* 转换为至 wchar_t* .

std::string filter;
// ...
LPCWSTR(filter.c_str()) // this does not work and causes the error!

如果您需要您的函数使用 std::string , 将其完全保留为 ANSI(使用 FindFirstFileA 、 FindNextFileA 和 WIN32_FIND_DATAA )。否则使用 std::wstring而是使用以 W 结尾的函数/结构而不是 A .

Windows header 定义 FindFirstFile作为FindFirstFileW如果UNICODE被定义并且FindFirstFileA除此以外。因此，对于通用解决方案，typedef a std::basic_string<TCHAR>并将其用作字符串类型。这样它在 UNICODE 时使用 std::wstring已定义，否则为 std::string。