Can you call Directory.GetFiles() with multiple filters?

If you have a large list of extensions to check you can use the following. I didn't want to create a lot of OR statements so i modified what lette wrote.

string supportedExtensions = "*.jpg,*.gif,*.png,*.bmp,*.jpe,*.jpeg,*.wmf,*.emf,*.xbm,*.ico,*.eps,*.tif,*.tiff,*.g01,*.g02,*.g03,*.g04,*.g05,*.g06,*.g07,*.g08";
foreach (string imageFile in Directory.GetFiles(_tempDirectory, "*.*", SearchOption.AllDirectories).Where(s => supportedExtensions.Contains(Path.GetExtension(s).ToLower())))
{
    //do work here
}

How about this:

private static string[] GetFiles(string sourceFolder, string filters, System.IO.SearchOption searchOption)
{
   return filters.Split('|').SelectMany(filter => System.IO.Directory.GetFiles(sourceFolder, filter, searchOption)).ToArray();
}

I found it here (in the comments): http://msdn.microsoft.com/en-us/library/wz42302f.aspx

For .NET 4.0 and later,

var files = Directory.EnumerateFiles("C:\\path", "*.*", SearchOption.AllDirectories)
            .Where(s => s.EndsWith(".mp3") || s.EndsWith(".jpg"));

For earlier versions of .NET,

var files = Directory.GetFiles("C:\\path", "*.*", SearchOption.AllDirectories)
            .Where(s => s.EndsWith(".mp3") || s.EndsWith(".jpg"));

edit: Please read the comments. The improvement that Paul Farry suggests, and the memory/performance issue that Christian.K points out are both very important.

for

var exts = new[] { "mp3", "jpg" };

You could:

public IEnumerable<string> FilterFiles(string path, params string[] exts) {
    return
        Directory
        .EnumerateFiles(path, "*.*")
        .Where(file => exts.Any(x => file.EndsWith(x, StringComparison.OrdinalIgnoreCase)));
}

• Don't forget the new .NET4 Directory.EnumerateFiles for a performance boost (What is the difference between Directory.EnumerateFiles vs Directory.GetFiles?)
• "IgnoreCase" should be faster than "ToLower" (.EndsWith("aspx", StringComparison.OrdinalIgnoreCase) rather than .ToLower().EndsWith("aspx"))

But the real benefit of EnumerateFiles shows up when you split up the filters and merge the results:

public IEnumerable<string> FilterFiles(string path, params string[] exts) {
    return 
        exts.Select(x => "*." + x) // turn into globs
        .SelectMany(x => 
            Directory.EnumerateFiles(path, x)
            );
}

It gets a bit faster if you don't have to turn them into globs (i.e. exts = new[] {"*.mp3", "*.jpg"} already).

Performance evaluation based on the following LinqPad test (note: Perf just repeats the delegate 10000 times) https://gist.github.com/zaus/7454021

( reposted and extended from 'duplicate' since that question specifically requested no LINQ: Multiple file-extensions searchPattern for System.IO.Directory.GetFiles )