通过搜索条件检索文件列表的最快方法-C＃

Question

I have a directory structure with txt files.

I want to get a list of file names where the modified/creation date is between a range.

So far, I have this:

        DirectoryInfo directory = new DirectoryInfo(@"C:\MotionWise\Manifest\000EC902F17F");
        DateTime from_date = DateTime.Now.AddMinutes(-300);
        DateTime to_date = DateTime.Now;
        List<FileInfo> files = directory.GetFiles("*", SearchOption.AllDirectories).Where(file => file.LastWriteTime >= from_date && file.LastWriteTime <= to_date).ToList();

Now,I am only interested in the full path name.

If I enumerate through the files list I can add the full path name to a new list/array etc. but this seems a waste of extra effort as I feel there is a way to do this in the lambada code?

If it can be done in the lambada code will not the selection by file info be too 'heavy'? Is there a way to just select full path name without 'loading' each entry into a file info?

I have been toying with the idea of executing the dir DOS command and capturing the output in the Process class.

Answer 1

If you're only interested in the paths don't use DirectoryInfo.GetFiles because it returns an array and because it is a FileInfo[] where each FileInfo object includes all informations that you're not interested in anyway. You can use File.GetLastWriteTime to get it.

Instead use Directory.EnumerateFiles which lazily returns only paths that are matching your filter criteria and the search pattern.

List<string> paths = Directory.EnumerateFiles(@"C:\MotionWise\Manifest\000EC902F17F", "*", SearchOption.AllDirectories)
    .Where(path => {
        DateTime lastWriteTime = File.GetLastWriteTime(path);
        return lastWriteTime >= from_date && lastWriteTime <= to_date;
    })
    .ToList();

Answer 2

Just Select on the FullName :

List<string> files = directory.GetFiles("*", SearchOption.AllDirectories)
                              .Where(file => file.LastWriteTime >= from_date && file.LastWriteTime <= to_date)
                              .Select(f => f.FullName)
                              .ToList();