按父,前一个和下一个id排序菜单节点

Question

我有一个小菜单,我想通过DB表ID来订购如下:

  public class Obj
    {
        public string Value { get; set; }
        public int? ParentNodeId { get; set; }
        public int? PreviousNodeId { get; set; }
        public int? NextNodeId { get; set; }
    }

 private IEnumerable<MenuNodeDTO> GetSortedMenuNodes(int menuId)
    {
        var nodes = LoadMenuNodes(menuId);
        foreach (MenuNode menuNode in nodes
            .Where(s => s.MenuItemId == null && s.ParentNodeId == null)
            .OrderBy(x => x?.PreviousNodeId)
            .Where(x => x.PreviousNodeId != x.Id))
        {
            MenuNodeDTO tmpMenuNode = new MenuNodeDTO();
            tmpMenuNode.MenuNodeDtoId = menuNode.Id;
            tmpMenuNode.MenuItemCode = menuNode.MenuItem?.Code;
            tmpMenuNode.ChildMenuNodes = GetChildNodes(menuNode).ToList();
            tmpMenuNode.MenuSettings = GetMenuSettings(menuNode).ToList();
            yield return tmpMenuNode;
        }
}

例:

Id = 1 MainMenuPoint1 ParentNodeId = null, PreviousNodeId = null, NextNodeId = 4
Id = 2 -> 1 ChildNodeFromPoint1 ParentNodeId = 1, PreviousNodeId = null, NextNodeId = null
Id = 3  --> ChildNodeFromFirstChildNode1 ParentNodeId = 2, PreviousNodeId = null, NextNodeId = null
Id = 4 MainMenuPoint2 ParentNodeId = null, PreviousNodeId = 1, NextNodeId = null

我对每个人的问题是,当id改变时,顺序不起作用.有人知道如何通过parentid,previousid和next id进行排序,每次检查所有关系的id？

Answer 1

 private IEnumerable<MenuNodeDTO> GetSortedNodes(Menu menu, MenuNode node)
        {
            List<MenuNodeDTO> items = new List<MenuNodeDTO>();

            var nodes = node != null ? node.ChildMenuNodes : menu.MenuNodes;
            var nextNode = node == null
                ? nodes.Where(c => c.PreviousNodeId == null && c.ParentNodeId == null).FirstOrDefault()
                : nodes.Where(c => c.ParentNodeId == node.Id && c.PreviousNodeId == null).FirstOrDefault();

            while (nextNode != null)
            {
                MenuNodeDTO tmpMenuNode = new MenuNodeDTO();
                tmpMenuNode.MenuNodeDtoId = nextNode.Id;
                tmpMenuNode.MenuItemCode = nextNode?.MenuItem?.Code;
                tmpMenuNode.ChildMenuNodes = this.GetSortedNodes(menu, nextNode).ToList();
                tmpMenuNode.MenuSettings = GetMenuSettings(nextNode).ToList();
                items.Add(tmpMenuNode);
                if (!nextNode.NextNodeId.HasValue) break;
                nextNode = nextNode.NextNode;
            }
            return items;
        }