csharp: DataRelation objects to represent a parent/child/Level relationship

/// <summary>
       ///
       /// </summary>
       /// <param name="sender"></param>
       /// <param name="e"></param>
       protected void Page_Load(object sender, EventArgs e)
       {
 
           var sections = new List<Section>
           {
               new Section { Id = 1, Name = "中国", ParentID = 0 },
               new Section { Id = 2, Name = "江西", ParentID = 1 },
               new Section { Id = 3, Name = "江苏", ParentID = 1 },
               new Section { Id = 4, Name = "南京", ParentID = 3 },
               new Section { Id = 5, Name = "南昌", ParentID = 2 },
               new Section { Id = 6, Name = "东湖区", ParentID = 5 },
               new Section { Id = 7, Name = "广东", ParentID = 1 },
               new Section { Id = 8, Name = "深圳", ParentID = 7 },
               new Section { Id = 9, Name = "罗湖区涂聚文", ParentID = 8 }
           };
 
           //sections = sections.OrderBy(x => x.ParentID).ThenBy(x => x.Name).ToList();
           //var stack = new Stack<Section>();
 
           //// Grab all the items without parents
           //foreach (var section in sections.Where(x => x.ParentID == default(int)).Reverse())
           //{
           //    stack.Push(section);
           //    sections.RemoveAt(0);
           //}
 
           //var output = new List<Section>();
           //while (stack.Any())
           //{
           //    var currentSection = stack.Pop();
 
           //    var children = sections.Where(x => x.ParentID == currentSection.Id).Reverse();
 
           //    foreach (var section in children)
           //    {
           //        stack.Push(section);
           //        sections.Remove(section);
           //    }
           //    output.Add(currentSection);
           //}
           //sections = output;
 
           List<MySection> mys = MenuHelper.GetMyMenuCollection(sections);
 
           //ResolveDDL<MySectionMenu>(mys);
 
           for (int i = 0; i < mys.Count; i++)
           {
                
 
               Response.Write(string.Format("ID:{0} ParentID: {1} TreeLevel: {2} Name:{3}<br/>", mys[i].Id, mys[i].ParentID, mys[i].TreeLevel,mys[i].Name));
           }
 
       }
 
 
       /// <summary>
       ///
       /// </summary>
       /// <typeparam name="T"></typeparam>
       /// <param name="mys"></param>
       protected void ResolveDDL<T>(List<T> mys) where T : MyBaseSection, new()
       {
 
           ResolveDDL<T>(mys, -1, true);
       }
       /// <summary>
       ///
       /// </summary>
       /// <typeparam name="T"></typeparam>
       /// <param name="mys"></param>
       /// <param name="currentId"></param>
       protected void ResolveDDL<T>(List<T> mys, int currentId) where T : MyBaseSection, new()
       {
           ResolveDDL<T>(mys, currentId, true);
       }
 
       /// <summary>
       /// 将一个树型结构放在一个下列列表中可供选择
       /// </summary>
       /// <typeparam name="T"></typeparam>
       /// <param name="currentId"></param>
       /// <param name="mys"></param>
       protected void ResolveDDL<T>(List<T> mys, int currentId, bool addRootNode) where T : MyBaseSection, new()
       {
           if (addRootNode)
           {
               // 所有节点的TreeLevel加一，然后添加根节点
               foreach (T my in mys)
               {
                   my.TreeLevel += 1;
               }
               T root = new T();
               root.Name = "--根节点--";
               root.Id = 0;
               root.TreeLevel = 0;
               mys.Insert(0, root);
           }
 
 
           // currentId==-1表示当前节点不存在
           if (currentId != -1)
           {
               // 本节点不可点击（也就是说当前节点不可能是当前节点的父节点）
               // 并且本节点的所有子节点也不可点击，你想如果当前节点跑到子节点的子节点，那么这些子节点就从树上消失了
               bool startChileNode = false;
               int startTreeLevel = 0;
               foreach (T my in mys)
               {
                   if (my.Id == currentId)
                   {
                       startTreeLevel = my.TreeLevel;
                       my.Enabled = false;
                       startChileNode = true;
                   }
                   else
                   {
                       if (startChileNode)
                       {
                           if (my.TreeLevel > startTreeLevel)
                           {
                               my.Enabled = false;
                           }
                           else
                           {
                               startChileNode = false;
                           }
                       }
                   }
               }
           }
       }
 
 
   }
 
   /// <summary>
   /// /
   /// </summary>
   public class Section
   {
       public int Id { get; set; }
       public string Name { get; set; }
       public int ParentID { get; set; }
   }
   /// <summary>
   ///
   /// </summary>
   public class MySection
   {
       public int Id { get; set; }
       public string Name { get; set; }
       public int ParentID { get; set; }
       public int TreeLevel { get; set; }
   }
   /// <summary>
   ///
   /// </summary>
   public class MySectionMenu : MyBaseSection
   {
 
   }
   /// <summary>
   ///
   /// </summary>
   public class MyBaseSection
   {
        public int Id
       {
           get;
           set;
       }
 
       public int ParentId
       {
           get;
           set;
       }
 
       public string Name
       {
           get;
           set;
       }
               /// <summary>
       /// 本菜单在树形结构中层级（从0开始）
       /// </summary>
       public int TreeLevel
       {
           get;
           set;
       }
 
       /// <summary>
       /// 是否可用（默认true）
       /// </summary>
       public bool Enabled
       {
           get;
           set;
       }
 
       /// <summary>
       /// 是否叶子节点（默认false）
       /// </summary>
       public bool IsTreeLeaf
       {
           get;
           set;
       }
 
 
   }
 
 
   /// <summary>
   ///
   /// </summary>
   public class MenuHelper
   {
 
       /// <summary>
       ///
       /// </summary>
       /// <param name="oldMenus"></param>
       /// <returns></returns>
       public static List<MySection> GetMyMenuCollection(List<Section> oldMenus)
       {
           List<MySection> newMenus = new List<MySection>();
           ResolveMenuCollection(oldMenus, newMenus, 0, 0);
 
           return newMenus;
       }
       /// <summary>
       ///
       /// </summary>
       /// <param name="oldMenus"></param>
       /// <param name="newMenus"></param>
       /// <param name="parentId"></param>
       /// <param name="level"></param>
       /// <returns></returns>
       private static int ResolveMenuCollection(List<Section> oldMenus, List<MySection> newMenus, int parentId, int level)
       {
           int count = 0;
           foreach (Section menu in oldMenus)
           {
               if (menu.ParentID == parentId)
               {
                   count++;
 
                   MySection my = new MySection();
                   newMenus.Add(my);
                   my.TreeLevel = level;
                   my.Id = menu.Id;             
                   my.Name = menu.Name;               
                   my.ParentID = menu.ParentID;      
 
 
                   level++;
                   int childCount = ResolveMenuCollection(oldMenus, newMenus, menu.Id, level);     
                   level--;
               }
           }
 
           return count;
       }
   }

显示结果：

ID:1 ParentID: 0 TreeLevel: 0 Name:中国
ID:2 ParentID: 1 TreeLevel: 1 Name:江西
ID:5 ParentID: 2 TreeLevel: 2 Name:南昌
ID:6 ParentID: 5 TreeLevel: 3 Name:东湖区
ID:3 ParentID: 1 TreeLevel: 1 Name:江苏
ID:4 ParentID: 3 TreeLevel: 2 Name:南京
ID:7 ParentID: 1 TreeLevel: 1 Name:广东
ID:8 ParentID: 7 TreeLevel: 2 Name:深圳
ID:9 ParentID: 8 TreeLevel: 3 Name:涂聚文