Directory Size Utility - Version 2

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Introduction

This is the second version of my previous directory size utility. If you haven't seen it, you can take a look here. Although it is the second version, it uses an older version of the .NET Framework - version 2.0. It improves on the first version in that it can ignore inaccessible files and directories without skipping everything that follows the inaccessible file or directory.

Requirements

This utility is written in Visual Studio 2013 Express, and you'll need to enable or install .NET Framework 2.0 if it is not already present. For details on how to do this, go here (Windows XP) or here (Windows 8), depending on your OS.

Recursively Listing Files

Unlike the previous version, we manually recurse over subdirectories to get each one's size. An inaccessible directory will throw an UnauthorizedAccessException in the recursive method. You may note that I've caught the generic Exception, but that's just me being lazy, modify it to your liking. Here's the function that does all the work. It calls itself recursively whenever it encounters a subdirectory.

static UInt64 GetFilesInDirectory(string directory, ref bool errors)
{
    UInt64 size = 0;
    
    DirectoryInfo di = new DirectoryInfo(directory);    try
    {
        // Get immediate subdirectories
        DirectoryInfo[] directories = di.GetDirectories("*", SearchOption.TopDirectoryOnly);
        if (directories != null)
        {
            foreach (DirectoryInfo dir in directories)
            {
                size += GetFilesInDirectory(dir.FullName, ref errors);  // Recursive call
            }
        }

        // Get files in this directory and add up sizes
        FileInfo[] files = di.GetFiles("*", SearchOption.TopDirectoryOnly);
        foreach (FileInfo file in files)
        {
            size += (UInt64)file.Length;
        }
    }
    catch (Exception ex)
    {
        errors = true; // Notify caller of error
    }

    return size;
}

To explain it simply, the method takes two arguments; the first specifies which directory to scan, and the second returns a flag indicating whether there were any errors accessing subdirectories. It calls DirectoryInfo.GetDirectories internally to get all subdirectories, calling itself recursively on each of these. It then calls DirectoryInfo.GetFiles and sums the sizes of all the files in the specified directory, adding them to the size returned by the recursive call.

Improvements

This version returns a more accurate size in case of errors. The previous .NET 4 version aborts all files and subdirectories following an access denial exception, but this one only fails on the inaccessible subdirectory.

Future Work

I have hardcoded the error message mechanism to show a single message in case of one or more access denials. You may modify the code as indicated in the comments to print a message per error. Future versions will include command line options to switch this behavior.

Conclusion

Bug reports and comments are welcome. I've only tested this on one OS, so your mileage may vary. Keep me posted.