Directory size

A C# method can calculate the total size of a directory. It considers each file. It returns the total bytes of all files.

This C# method is useful for compression or file transfers. We determine the size of a directory. We can detect changes in directory sizes.

Example

We can use the Directory class and a foreach-loop. We write our own custom method—we sum the length of each file, returning the total size in bytes.

using System;
using System.IO;

class Program
{
    static void Main()
    {
        var size = GetDirectorySize(@"programs\");
        Console.WriteLine(size);
    }

    static long GetDirectorySize(string path)
    {
        // Get array of all file names.
        string[] files = Directory.GetFiles(path, "*.*");

        // Calculate total bytes of all files in a loop.
        long totalBytes = 0;
        foreach (string name in files)
        {
            // Use FileInfo to get length of each file.
            FileInfo info = new FileInfo(name);
            totalBytes += info.Length;
        }
        // Return total size
        return totalBytes;
    }
}
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All directories

To get files in nested folders, use the SearchOption.AllDirectories argument. This returns an array with files from subdirectories.

SearchOption.AllDirectories
"*.*"
"*.png"

We measured directory sizes in bytes. We can use a combination of Directory methods and FileInfo objects to sum the bytes.