Multiple file-extensions searchPattern for System.IO.Directory.GetFiles

Question

What is the syntax for setting multiple file-extensions as searchPattern on Directory.GetFiles()? For example filtering out files

Answer 1

var filteredFiles = Directory
    .GetFiles(path, "*.*")
    .Where(file => file.ToLower().EndsWith("aspx") || file.ToLower().EndsWith("ascx"))
    .ToList();

Edit 2014-07-23

You can do this in .NET 4.5 for a faster enumeration:

var filteredFiles = Directory
    .EnumerateFiles(path) //<--- .NET 4.5
    .Where(file => file.ToLower().EndsWith("aspx") || file.ToLower().EndsWith("ascx"))
    .ToList();

Directory.EnumerateFiles in MSDN

Answer 2

Just would like to say that if you use FileIO.FileSystem.GetFiles instead of Directory.GetFiles, it will allow an array of wildcards.

For example:

Dim wildcards As String() = {"*.html", "*.zip"}
Dim ListFiles As List(Of String) = FileIO.FileSystem.GetFiles(directoryyouneed, FileIO.SearchOption.SearchTopLevelOnly, wildcards).ToList

Answer 3

I like this method, because it is readable and avoids multiple iterations of the directory:

var allowedExtensions = new [] {".doc", ".docx", ".pdf", ".ppt", ".pptx", ".xls", ".xslx"}; 
var files = Directory
    .GetFiles(folder)
    .Where(file => allowedExtensions.Any(file.ToLower().EndsWith))
    .ToList();

Answer 4

Instead of the EndsWith function, I would choose to use the Path.GetExtension() method instead. Here is the full example:

var filteredFiles = Directory.EnumerateFiles( path )
.Where(
    file => Path.GetExtension(file).Equals( ".aspx", StringComparison.OrdinalIgnoreCase ) ||
            Path.GetExtension(file).Equals( ".ascx", StringComparison.OrdinalIgnoreCase ) );

or:

var filteredFiles = Directory.EnumerateFiles(path)
.Where(
    file => string.Equals( Path.GetExtension(file), ".aspx", StringComparison.OrdinalIgnoreCase ) ||
            string.Equals( Path.GetExtension(file), ".ascx", StringComparison.OrdinalIgnoreCase ) );

(Use StringComparison.OrdinalIgnoreCase if you care about performance: MSDN string comparisons)

Answer 5

I would try to specify something like

var searchPattern = "as?x";

it should work.

Answer 6

I fear you will have to do somthing like this, I mutated the regex from here.

var searchPattern = new Regex(
    @"$(?<=\.(aspx|ascx))", 
    RegexOptions.IgnoreCase);
var files = Directory.EnumerateFiles(path)
    .Where(f => searchPattern.IsMatch(f))
    .ToList();