Asp.net mvc 3 MvcSiteMap仅显示根节点

我正在尝试使用DynamicNodeProvider在MVC3中创建一个多级站点地图。但仅显示根节点。请指导我代码中的问题所在。 我定义了一个类来覆盖GetDynamicNodeCollection，如下所示：

            public class UserJourneyNavigationProvider : DynamicNodeProviderBase
            {
                private List<NavigationGroups> NavigationGroups { get; set; }

                public UserJourneyNavigationProvider()
                {
                }

                public UserJourneyNavigationProvider(List<NavigationGroups> NavigationGroups)
                {
                    this.NavigationGroups = NavigationGroups;
                }

                public override IEnumerable<DynamicNode> GetDynamicNodeCollection()
                {
                    // Build value 
                    var returnValue = new List<DynamicNode>();

                    NavigationGroups ng1 = new NavigationGroups();
                    ng1.CategoryName = "Menu1";
                    NavigationGroups ng2 = new NavigationGroups();
                    ng2.CategoryName = "Menu2";
                    NavigationGroups ng3 = new NavigationGroups();
                    ng3.CategoryName = "Menu3";
                    NavigationGroups ng4 = new NavigationGroups();
                    ng4.CategoryName = "Menu4";
                    NavigationGroups ng5 = new NavigationGroups();
                    ng5.CategoryName = "Menu5";
                    NavigationGroups ng6 = new NavigationGroups();
                    ng6.CategoryName = "Menu6";
                    NavigationGroups ng7 = new NavigationGroups();
                    ng7.CategoryName = "Menu7";
                    NavigationGroups ng8 = new NavigationGroups();
                    ng8.CategoryName = "Menu8";
                    NavigationGroups ng9 = new NavigationGroups();
                    ng9.CategoryName = "Menu9";
                    NavigationGroups ng10 = new NavigationGroups();
                    ng10.CategoryName = "Menu10";

                    ng1.ChildCategory = new List<NavigationGroups>();
                    ng1.ChildCategory.Add(ng2);
                    ng1.ChildCategory.Add(ng3);
                    ng1.ChildCategory.Add(ng4);

                    ng5.ChildCategory = new List<NavigationGroups>();
                    ng5.ChildCategory.Add(ng6);
                    ng5.ChildCategory.Add(ng7);
                    ng5.ChildCategory.Add(ng8);

                    ng7.ChildCategory = new List<NavigationGroups>();
                    ng7.ChildCategory.Add(ng9);
                    ng7.ChildCategory.Add(ng10);

                    int i = 1;
                    ng1.CategoryId = (i++).ToString();
                    ng2.CategoryId = (i++).ToString();
                    ng3.CategoryId = (i++).ToString();
                    ng4.CategoryId = (i++).ToString();
                    ng5.CategoryId = (i++).ToString();
                    ng6.CategoryId = (i++).ToString();
                    ng7.CategoryId = (i++).ToString();
                    ng8.CategoryId = (i++).ToString();
                    ng9.CategoryId = (i++).ToString();
                    ng10.CategoryId = (i++).ToString();

                    NavigationGroups = new List<NavigationGroups>();
                    NavigationGroups.Add(ng1);
                    NavigationGroups.Add(ng5);

                    NavigationLinkGenerator(NavigationGroups, returnValue, "Home");

                    return returnValue;
                }

                private void NavigationLinkGenerator(List<NavigationGroups> navGroups, List<DynamicNode> returnValue, string parentKey)
                {
                    foreach (NavigationGroups navGroup in navGroups)
                    {
                        DynamicNode node = new DynamicNode();
                        node.Controller = "Home";
                        node.Action = "ProcessActionLink";
                        node.Title = navGroup.CategoryName;
                        node.Description = navGroup.CategoryName;

                        node.ChangeFrequency = MvcSiteMapProvider.ChangeFrequency.Always;

                        node.Key = navGroup.CategoryId;

                        if (!string.IsNullOrWhiteSpace(parentKey))
                            node.ParentKey = parentKey;

                        if (navGroup.ChildCategory != null && navGroup.ChildCategory.Count > 0)
                        {
                            NavigationLinkGenerator(navGroup.ChildCategory, returnValue, navGroup.CategoryId);
                        }

                        returnValue.Add(node);
                    }
                }
            }

              <mvcSiteMapNode title="Home"  controller="Home" action="Index" key="Home">
                  <mvcSiteMapNode title="" controller="Home" action="ProcessActionLink" dynamicNodeProvider="Business.Layer.UserJourneyNavigationProvider, Business.Layer" />
              </mvcSiteMapNode>

---

已解决问题：）应在递归之前添加节点。由于这是您自己的错误，与sitemap provider无关，我建议删除此问题。提前谢谢。

            @Html.MvcSiteMap().Menu(false, true, true)