How to check whether 2 DirectoryInfo objects are pointing to the same directory?

Question

I have 2 DirectoryInfo objects and want to check if they are pointing to the same directory. Besides comparing their Fullname, are there any other better ways

Answer 1

Some extension methods that I wrote for a recent project includes one that will do it:

    public static bool IsSame(this DirectoryInfo that, DirectoryInfo other)
    {
        // zip extension wouldn't work here because it truncates the longer 
        // enumerable, resulting in false positive

        var e1 = that.EnumeratePathDirectories().GetEnumerator();
        var e2 = other.EnumeratePathDirectories().GetEnumerator();

        while (true)
        {
            var m1 = e1.MoveNext();
            var m2 = e2.MoveNext();
            if (m1 != m2) return false; // not same length
            if (!m1) return true; // finished enumerating with no differences found

            if (!e1.Current.Name.Trim().Equals(e2.Current.Name.Trim(), StringComparison.InvariantCultureIgnoreCase))
                return false; // current folder in paths differ
        }
    }

    public static IEnumerable EnumeratePathDirectories(this DirectoryInfo di)
    {
        var stack = new Stack();

        DirectoryInfo current = di;

        while (current != null)
        {
            stack.Push(current);
            current = current.Parent;
        }

        return stack;
    }

    // irrelevant for this question, but still useful:

    public static bool IsSame(this FileInfo that, FileInfo other)
    {
        return that.Name.Trim().Equals(other.Name.Trim(), StringComparison.InvariantCultureIgnoreCase) &&
               that.Directory.IsSame(other.Directory);
    }

    public static IEnumerable EnumeratePathDirectories(this FileInfo fi)
    {
        return fi.Directory.EnumeratePathDirectories();
    }

    public static bool StartsWith(this FileInfo fi, DirectoryInfo directory)
    {
        return fi.Directory.StartsWith(directory);
    }

    public static bool StartsWith(this DirectoryInfo di, DirectoryInfo directory)
    {
        return di.EnumeratePathDirectories().Any(d => d.IsSame(directory));
    }