Circular linkedlist in C#

 class CustomCircularLinkedList<T>
    {
        public CircularLinkedListItem<T> RootNode;
        public int Count { set; get; }

        public void Add(T value)
        {
            CircularLinkedListItem<T> newNode = new CircularLinkedListItem<T>(value);

            if (RootNode == null)
            {
                this.RootNode = newNode;
                Count++;
                return;
            }

            CircularLinkedListItem<T> node = this.RootNode;

            while (node.NextNode != null)
            {
                node = node.NextNode;
            }

            node.NextNode = newNode;
            newNode.PreviousNode = node;
//This distinguishes double and circular linkedlist
            this.RootNode.PreviousNode = newNode;
        }
    }

    class CircularLinkedListItem<T>
    {
        public CircularLinkedListItem<T> PreviousNode { set; get; }
        public CircularLinkedListItem<T> NextNode { set; get; }
        public T NodeItem { set; get; }

        public CircularLinkedListItem(T value)
        {
            this.NodeItem = value;
        }
    }