数据准备

假设菜单表设计为：id、pid、name、url，其中pid表示父级菜单id，约定pid=-1为一级菜单。 这里用Hashtable来模拟，数据如下：

List
    
      listMenu = new List
     
      ();            Hashtable ht1 = new Hashtable();            ht1.Add("id", 1);            ht1.Add("pid", -1);            ht1.Add("url", "/");            ht1.Add("name", "首页");            listMenu.Add(ht1);            Hashtable ht2 = new Hashtable();            ht2.Add("id", 2);            ht2.Add("pid", -1);            ht2.Add("url", "/news");            ht2.Add("name", "资讯");            listMenu.Add(ht2);            Hashtable ht3 = new Hashtable();            ht3.Add("id", 3);            ht3.Add("pid", 2);            ht3.Add("url", "/news/hot");            ht3.Add("name", "热点");            listMenu.Add(ht3);            Hashtable ht4 = new Hashtable();            ht4.Add("id", 4);            ht4.Add("pid", 2);            ht4.Add("url", "/news/latest");            ht4.Add("name", "滚动新闻");            listMenu.Add(ht4);            Hashtable ht5 = new Hashtable();            ht5.Add("id", 5);            ht5.Add("pid", 4);            ht5.Add("url", "/news/latest/international");            ht5.Add("name", "国际快讯");            listMenu.Add(ht5);            Hashtable ht6 = new Hashtable();            ht6.Add("id", 6);            ht6.Add("pid", -1);            ht6.Add("url", "/domain");            ht6.Add("name", "行业");            listMenu.Add(ht6);            Hashtable ht7 = new Hashtable();            ht7.Add("id", 7);            ht7.Add("pid", 5);            ht7.Add("url", "/news/latest/international/politics");            ht7.Add("name", "政治");            listMenu.Add(ht7);            Hashtable ht8 = new Hashtable();            ht8.Add("id", 8);            ht8.Add("pid", 5);            ht8.Add("url", "/news/latest/international/military");            ht8.Add("name", "军事");            listMenu.Add(ht8);
     
    

定义一个菜单树model

public class MenuTreeViewModel    {        public Hashtable item { set; get; }        public List
    
      children { set; get; }    }
    

递归算法实现

算法很简单，每次根据父级菜单id去查找子菜单 1.原始实现

public static List
    
      GetMenuTree(List
     
       list,int pid)        {            List
      
        tree = new List
       
        ();            var children = list.Where(m => m["pid"].ToString() == pid.ToString()).ToList();            if (children.Count > 0)            {                for (var i = 0; i < children.Count; i++)                {                    MenuTreeViewModel itemMenu = new MenuTreeViewModel();                    itemMenu.item = children[i];                    itemMenu.children = GetMenuTree(list, Convert.ToInt32(children[i]["id"]));                    tree.Add(itemMenu);                }            }            return tree;        }
       
      
     
    

2.利用Func委托实现

public static List
    
      GetMenuTree(List
     
       list,int pid)        {            Func
      
       > func = null;            func = new Func
       
        >(m => {                List
        
          t = new List
         
          (); foreach (var item in list.Where(h => h["pid"].ToString() == m.ToString())) { var childs = func(Convert.ToInt32(item["id"])); t.Add(new MenuTreeViewModel() { item=item, children=childs }); } return t; }); return func(-1); }
         
        
       
      
     
    

调用方式：GetMenuTree(listMenu, -1);//listMenu即上边的数据准备

效果