Best way to iterate folders and subfolders

Question

What's the best way to iterate folders and subfolders to get file size, total number of files, and total size of folder in each folder starting at a specified location?

Answer 1

If you're using .NET 4, you may wish to use the System.IO.DirectoryInfo.EnumerateDirectories and System.IO.DirectoryInfo.EnumerateFiles methods. If you use the Directory.GetFiles method as other posts have recommended, the method call will not return until it has retrieved ALL the entries. This could take a long time if you are using recursion.

From the documentation:

The EnumerateFilesand GetFiles methods differ as follows:

• When you use EnumerateFiles, you can start enumerating the collection of FileInfo objects before the whole collection is returned.
• When you use GetFiles, you must wait for the whole array of FileInfo objects to be returned before you can access the array.

Therefore, when you are working with many files and directories, EnumerateFiles can be more efficient.

Answer 2

Use Directory.GetFiles(). The bottom of that page includes an example that's fully recursive.

Note: Use Chris Dunaway's answer below for a more modern approach when using .NET 4 and above.

// For Directory.GetFiles and Directory.GetDirectories
// For File.Exists, Directory.Exists
using System;
using System.IO;
using System.Collections;

public class RecursiveFileProcessor 
{
    public static void Main(string[] args) 
    {
        foreach(string path in args) 
        {
            if(File.Exists(path)) 
            {
                // This path is a file
                ProcessFile(path); 
            }               
            else if(Directory.Exists(path)) 
            {
                // This path is a directory
                ProcessDirectory(path);
            }
            else 
            {
                Console.WriteLine("{0} is not a valid file or directory.", path);
            }        
        }        
    }

    // Process all files in the directory passed in, recurse on any directories 
    // that are found, and process the files they contain.
    public static void ProcessDirectory(string targetDirectory) 
    {
        // Process the list of files found in the directory.
        string [] fileEntries = Directory.GetFiles(targetDirectory);
        foreach(string fileName in fileEntries)
            ProcessFile(fileName);

        // Recurse into subdirectories of this directory.
        string [] subdirectoryEntries = Directory.GetDirectories(targetDirectory);
        foreach(string subdirectory in subdirectoryEntries)
            ProcessDirectory(subdirectory);
    }
    
    // Insert logic for processing found files here.
    public static void ProcessFile(string path) 
    {
        Console.WriteLine("Processed file '{0}'.", path);       
    }
}

Answer 3

To iterate through all directories sub folders and files, no matter how much sub folder and files are.

string [] filenames;
 fname = Directory.GetFiles(jak, "*.*", SearchOption.AllDirectories).Select(x => Path.GetFileName(x)).ToArray();

then from array you can get what you want via a loop or as you want.

Answer 4

Here's an example using Peter's suggestion above and recursion.

using System;
using System.IO;

namespace FileSystemUtils
{
    class Program
    {
        static void Main(string[] args)
        {
            string folderPath = "C:\\docs";

            DirectoryInfo startDir = new DirectoryInfo(folderPath);

            RecurseFileStructure recurseFileStructure = new RecurseFileStructure();
            recurseFileStructure.TraverseDirectory(startDir);
        }

        public class RecurseFileStructure
        {
            public void TraverseDirectory(DirectoryInfo directoryInfo)
            {
                var subdirectories = directoryInfo.EnumerateDirectories();

                foreach (var subdirectory in subdirectories)
                {
                    TraverseDirectory(subdirectory);
                }

                var files = directoryInfo.EnumerateFiles();

                foreach (var file in files)
                {
                    HandleFile(file);
                }
            }

            void HandleFile(FileInfo file)
            {
                Console.WriteLine("{0}", file.Name);
            }
        }
    }
}

Answer 5

To iterate through files and folders you would normally use the DirectoryInfo and FileInfo types. The FileInfo type has a Length property that returns the file size in bytes.

I think you must write your own code to iterate through the files and calculate the total file size, but it should be a quite simple recursive function.

Answer 6

Note that you will need to perform validation checks.

string[] fileNames = Directory.GetFiles("c:\\", "*.*", SearchOption.AllDirectories);
int fileCount = fileNames.Count();
long fileSize = fileNames.Select(file => new FileInfo(file).Length).Sum(); // in bytes