Question

I would like to optimize the following method, that returns the total file count of the specified folder and all subfolders, for speed and memory usage; any advice is appreciated.

Thanks.

private int countfiles(string srcdir)
{
    try
    {
        DirectoryInfo dir = new DirectoryInfo(srcdir);

        //if the source dir doesn't exist, throw an exception
        if (!dir.Exists)
            throw new ArgumentException("source dir doesn't exist -> " + srcdir);

        int count = dir.GetFiles().Length;

        //loop through each sub directory in the current dir
        foreach (DirectoryInfo subdir in dir.GetDirectories())
        {
            //recursively call this function over and over again
            count += countfiles(subdir.FullName);
        }

        //cleanup
        dir = null;

        return count;
    }
    catch (Exception exc)
    {
        MessageBox.Show(exc.Message);
        return 0;
    }           
}

So I did some benchmarking with the suggestions that were proposed. Here are my findings:

• My method, with recursion, is the slowest finding 9062 files in a directory tree in 6.234 seconds.

• @Matthew’s answer, using SearchOption.AllDirectories, is the fastest finding the same 9062 files in 4.546 seconds

• @Jeffery’s answer, using LINQ, is in the middle of the pack finding the same 9062 files in 5.562 seconds.

Thank you everyone for your suggestions.

Answer 1

Could you not change the entire method to:

int count = Directory.GetFiles(path, "*.*", SearchOption.AllDirectories).Length;