Recursive file list

Directories are often nested. Sometimes we need a list of files in a folder, and also those in each subdirectory.

The .NET Framework allows a SearchOption.AllDirectories argument to the Directory.GetFiles and EnumerateFiles methods. This is the easiest way to recursively get files.

GetFiles

This program gets a string array of all the files at a certain level of the file system. It also covers all sublevels. Then, it loops through the result and prints the file paths.

using System;
using System.IO;

class Program
{
    static void Main()
    {
        // Get list of files in the specific directory.
        // ... Please change the first argument.
        string[] files = Directory.GetFiles("C:\\PerlsComStage\\",
            "*.*",
            SearchOption.AllDirectories);

        // Display all the files.
        foreach (string file in files)
        {
            Console.WriteLine(file);
        }
    }
}
C:\PerlsComStage\Default.aspx
C:\PerlsComStage\Global.asax
C:\PerlsComStage\Web.config
C:\PerlsComStage\bin\PerlsComWebProject1.dll
C:\PerlsComStage\bin\PerlsComWebProject1.pdb

List example

We convert the array returned by Directory.GetFiles to a List. Then we pass the List instance to another method and display the value returned by its Count property.

using System;
using System.Collections.Generic;
using System.IO;

class Program
{
    static void Main()
    {
        // Make sure directory exists before using this!
        var files = new List<string>(Directory.GetFiles("C:\\folder",
            "*.*",
            SearchOption.AllDirectories));
        Method(files);
    }

    static void Method(List<string> files)
    {
        Console.WriteLine(files.Count);
    }
}
22

EnumerateFiles

This method receives the directory path as its first argument. The second two arguments are optional. To recurse through directories, use AllDirectories.

using System;
using System.IO;

class Program
{
    static void Main()
    {
        // Call EnumerateFiles in a foreach-loop.
        foreach (string file in Directory.EnumerateFiles(@"c:\files",
            "*.*",
            SearchOption.AllDirectories))
        {
            // Display file path.
            Console.WriteLine(file);
        }
    }
}
c:\files\index.html
c:\files\style.css
c:\files\images\logo.png
c:\files\images\picture.jpg

Notes, custom methods

It is possible to develop a method that uses recursion, or stack-based recursion, to scan directories. This is fun to do, and may be a good learning experience.

Directory.GetFiles method can perform a recursive file listing. Instead of custom implementations, this method overload provides a clearer, simpler abstraction.