/// <summary>
        /// Initializes a custom instance of the MutexViewModel class.
        /// </summary>
        /// <param name="parentControl"></param>
        public MutexViewModel(RankingsControlViewModel parentControl)
        {
            // Validate arguments.
            if ( parentControl == null )
            {
                throw new ArgumentNullException("parentControl");
            }

            // Assign argument values to member fields.
            _parentControl = parentControl;
        }
        public RankingsControl()
        {
            InitializeComponent();

            DataContext = new RankingsControlViewModel();
        }