不用FileExists，就用Windows API能否判断c:\a.txt是否存在？

Question

不用FileExists，就用Windows API能否判断c:\a.txt是否存在？

Answer 1

SysUtils中的实现：function FileExists(const FileName: string): Boolean;
begin
  Result := FileAge(FileName) <> -1;
end;function FileAge(const FileName: string): Integer;
var
  Handle: THandle;
  FindData: TWin32FindData;
  LocalFileTime: TFileTime;
begin
  Handle := FindFirstFile(PChar(FileName), FindData);
  if Handle <> INVALID_HANDLE_VALUE then
  begin
    Windows.FindClose(Handle);
    if (FindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY) = 0 then
    begin
      FileTimeToLocalFileTime(FindData.ftLastWriteTime, LocalFileTime);
      if FileTimeToDosDateTime(LocalFileTime, LongRec(Result).Hi,
        LongRec(Result).Lo) then Exit;
    end;
  end;
  Result := -1;
end;

Answer 2

Delphi自带的FileExists有问题,时常文件存在却判断为不存在
下面我给一段CPP的代码,如果需要的话就自己改一下就成Delphi的了,现在有点忙,Sorry!bool __fastcall FileExists(AnsiString FileName)
{
   HANDLE FileHandle = CreateFile(FileName.c_str(),
                                  NULL,
                                  FILE_SHARE_READ |
                                  FILE_SHARE_WRITE,
                                  NULL,
                                  OPEN_EXISTING,
                                  FILE_ATTRIBUTE_ARCHIVE |
                                  FILE_ATTRIBUTE_HIDDEN |
                                  FILE_ATTRIBUTE_NORMAL |
                                  FILE_ATTRIBUTE_READONLY |
                                  FILE_ATTRIBUTE_SYSTEM,
                                  NULL
                                 );
   if (FileHandle == INVALID_HANDLE_VALUE)
      return false;
   CloseHandle(FileHandle);
   return true;
}