求一linq查询，得到如下结果

C# code

public partial class Default2 : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        IList<Area> list = new List<Area>();        list.Add(new Area() { Uid=1, Pid=0, Name="电信" });        list.Add(new Area() { Uid=2, Pid=0, Name="联通" });        list.Add(new Area() { Uid=3, Pid=0, Name="移动" });        list.Add(new Area() { Uid=4, Pid=1, Name="电信一区" });        list.Add(new Area() { Uid=5, Pid=1, Name="电信二区" });        // 用linq查询得到 uid、name        // name中显示父级-子级-子子级。。。。，只要最后一级        // 结果：        //uid                 name                                                //2                    联通                                  //3                    移动                                      //4                    电信-电信一区                                         //5                    电信-电信二区    }}public class Area{    public int Uid { get; set; }    public int Pid { get; set; }// 父ID    public string Name { get; set; }}

C# code

void Main(){     IList<Area> list = new List<Area>();        list.Add(new Area() { Uid=1, Pid=0, Name="电信" });        list.Add(new Area() { Uid=2, Pid=0, Name="联通" });        list.Add(new Area() { Uid=3, Pid=0, Name="移动" });        list.Add(new Area() { Uid=4, Pid=1, Name="电信一区" });        list.Add(new Area() { Uid=5, Pid=1, Name="电信二区" });            var query=from  l in list              select new                 {                  Uid=l.Uid,                  Name=l.Pid==0?l.Name : list.First(m=>m.Uid==l.Pid).Name+"-"+l.Name                };     }public class Area{    public int Uid { get; set; }    public int Pid { get; set; }// 父ID    public string Name { get; set; }}
[解决办法]
C# code
using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            List<Area> list = new List<Area>();            list.Add(new Area() { Uid = 1, Pid = 0, Name = "电信" });            list.Add(new Area() { Uid = 2, Pid = 0, Name = "联通" });            list.Add(new Area() { Uid = 3, Pid = 0, Name = "移动" });            list.Add(new Area() { Uid = 4, Pid = 1, Name = "电信一区" });            list.Add(new Area() { Uid = 5, Pid = 1, Name = "电信二区" });            list.Add(new Area() { Uid = 6, Pid = 5, Name = "电信二区之一" });            Func<int, int> FindRoot = (x) => x;            FindRoot = (x) => list.First(y => y.Uid == x).Pid == 0 ? list.First(y => y.Uid == x).Uid : FindRoot(list.First(y => y.Uid == x).Pid);            var query = from l in list                        select new                        {                            Uid = l.Uid,                            Name = l.Pid == 0 ? l.Name : list.First(m => m.Uid == FindRoot(l.Uid)).Name + "-" + l.Name                        };            foreach (var item in query)            {                Console.WriteLine(item.Uid + "," + item.Name);            }        }    }    class Area    {        public int Uid { get; set; }        public int Pid { get; set; }        public string Name { get; set; }    }}
[解决办法]
C# code
            IList<Area> list = new List<Area>();            list.Add(new Area() { Uid = 1, Pid = 0, Name = "电信" });            list.Add(new Area() { Uid = 2, Pid = 0, Name = "联通" });            list.Add(new Area() { Uid = 3, Pid = 0, Name = "移动" });            list.Add(new Area() { Uid = 4, Pid = 1, Name = "电信一区" });            list.Add(new Area() { Uid = 5, Pid = 1, Name = "电信二区" });            list.Add(new Area() { Uid = 6, Pid = 0, Name = "Test" });            list.Add(new Area() { Uid = 7, Pid = 6, Name = "Test1" });            list.Add(new Area() { Uid = 8, Pid = 7, Name = "Test11" });            Console.WriteLine("uid\t\tname");            foreach (var area in list.Where(a => !list.Any(l => l.Pid == a.Uid)))            {                Console.WriteLine("{0}\t\t{1}", area.Uid, area.Name);            }            Console.ReadLine(); 
 
[解决办法]
晕，看了阿非的程序才明白你说的只要最后一级是什么意思。

一个优秀的程序员应该学会设计良好的，覆盖主要情况和边界条件的测试用例。很明显，你没有设计多于2级的情况的用例。

其实这个用linq做并不太好。

C# code
using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            List<Area> list = new List<Area>();            list.Add(new Area() { Uid = 1, Pid = 0, Name = "电信" });            list.Add(new Area() { Uid = 2, Pid = 0, Name = "联通" });            list.Add(new Area() { Uid = 3, Pid = 0, Name = "移动" });            list.Add(new Area() { Uid = 4, Pid = 1, Name = "电信一区" });            list.Add(new Area() { Uid = 5, Pid = 1, Name = "电信二区" });            list.Add(new Area() { Uid = 6, Pid = 5, Name = "电信二区之一" });            list.Add(new Area() { Uid = 7, Pid = 0, Name = "Test" });            list.Add(new Area() { Uid = 8, Pid = 7, Name = "Test1" });            list.Add(new Area() { Uid = 9, Pid = 8, Name = "Test11" });            list.Add(new Area() { Uid = 10, Pid = 9, Name = "Test111" });            Func<Tuple<int, string>, Tuple<int, string>> FindRoot = (x) => x;            FindRoot =                 (x) =>                     list.First(y => y.Uid == x.Item1).Pid == 0 ?                     new Tuple<int, string>(list.First(y => y.Uid == x.Item1).Uid, list.First(y => y.Uid == x.Item1).Name + "-" + x.Item2) :                    FindRoot(new Tuple<int, string>(list.First(y => y.Uid == x.Item1).Pid, list.First(y => y.Uid == x.Item1).Name + "-" + x.Item2));            var query = from x in list                        where !list.Any(y => y.Pid == x.Uid)                        select new                        {                            Uid = x.Uid,                            Name = x.Pid == 0 ? x.Name : FindRoot(new Tuple<int, string>(x.Uid, "")).Item2.TrimEnd('-')                        };            foreach (var item in query)            {                Console.WriteLine(item.Uid + "," + item.Name);            }        }    }    class Area    {        public int Uid { get; set; }        public int Pid { get; set; }        public string Name { get; set; }    }}