How to filter Directory.EnumerateFiles with multiple criteria?

Question

I have the following code:

List<string> result = new List<string>();  foreach (string file in Directory.EnumerateFiles(path,"*.*",         SearchOption.AllDirectories)       .Where(s => s.EndsWith(".mp3") || s.EndsWith(".wma")))        {           result.Add(file);                         } 

It works fine and does what I need. Except for one small thing. I would like to find a better way to filter on multiple extensions. I would like to use a string array with filters such as this:

string[] extensions = { "*.mp3", "*.wma", "*.mp4", "*.wav" }; 

What is the most efficient way to do this using NET Framework 4.0/LINQ? Any suggestions?

I'd appreciate any help being an occasional programmer :-)

Answer 1

I created some helper methods to solve this which I blogged about earlier this year.

One version takes a regex pattern \.mp3|\.mp4, and the other a string list and runs in parallel.

public static class MyDirectory {   // Regex version    public static IEnumerable<string> GetFiles(string path,                         string searchPatternExpression = "",                        SearchOption searchOption = SearchOption.TopDirectoryOnly)    {       Regex reSearchPattern = new Regex(searchPatternExpression, RegexOptions.IgnoreCase);       return Directory.EnumerateFiles(path, "*", searchOption)                       .Where(file =>                                reSearchPattern.IsMatch(Path.GetExtension(file)));    }     // Takes same patterns, and executes in parallel    public static IEnumerable<string> GetFiles(string path,                         string[] searchPatterns,                         SearchOption searchOption = SearchOption.TopDirectoryOnly)    {       return searchPatterns.AsParallel()              .SelectMany(searchPattern =>                      Directory.EnumerateFiles(path, searchPattern, searchOption));    } }