public void ClearLink(int slot)
        {
            IHasLinks props_links = entity_props as IHasLinks;

            if (props_links != null)
            {
                props_links.EntityLinks[slot] = EntityGuid.Empty;
            }
        }
        public void AssignLink(int slot, Guid guid)
        {
            IHasLinks props_links = entity_props as IHasLinks;

            if (props_links != null)
            {
                props_links.EntityLinks[slot] = new EntityGuid(guid);
            }
        }
        public Guid GetLinkGUID(int slot)
        {
            IHasLinks props_links = entity_props as IHasLinks;

            return((props_links == null) ? Guid.Empty : props_links.EntityLinks[slot]);
        }