Check if path is in directory.

Extensions.cs

    public static bool IsInDirectory(this FileInfo file, DirectoryInfo directory) => file.Directory?.IsInDirectory(directory) ?? false;

    [SuppressMessage("Globalization", "CA1309", Justification = "Path comparison")]
    public static bool IsInDirectory(this DirectoryInfo path, DirectoryInfo directory)
        => path.Parent != null && (path.Parent.FullName.Equals(directory.FullName, StringComparison.InvariantCultureIgnoreCase) || path.Parent.IsInDirectory(directory));