[
  {
    "children":[
      {
        "children":[

        ],
        "username":"username2",
        "password":"password2",
        "id":"2",
        "pId":"1",
        "name":"节点2"
      },
      {
        "children":[

        ],
        "username":"username2",
        "password":"password2",
        "id":"A2",
        "pId":"1",
        "name":"节点2"
      }
    ],
    "username":"username1",
    "password":"password1",
    "id":"1",
    "pId":"0",
    "name":"节点1"
  },
  {
    "children":[

    ],
    "username":"username1",
    "password":"password1",
    "id":"A1",
    "pId":"0",
    "name":"节点1"
  }
]

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MyTree.Abs
{
  public abstract class TreeObejct
  {
    public string id { set; get; }
    public string pId { set; get; }
    public string name { set; get; }
    public IList<TreeObejct> children = new List<TreeObejct>();
    public virtual void Addchildren(TreeObejct node)
    {
      this.children.Add(node);
    }
  }
}

using MyTree.Abs;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MyTree.Models
{
  public class TreeModel : TreeObejct
  {
    public string username { set; get; }
    public string password { set; get; }
  }
}

    public static IList<TreeObejct> GetData(int number = 11)
    {
      IList<TreeObejct> datas = new List<TreeObejct>();
      for (int i = 1; i < number; i++)
      {
        datas.Add(new TreeModel
        {
          id = i.ToString(),
          pId = (i - 1).ToString(),
          name = "节点" + i,
          username = "username" + i,
          password = "password" + i
        });
        datas.Add(new TreeModel
        {
          id = "A" + i.ToString(),
          pId = (i - 1).ToString(),
          name = "节点" + i,
          username = "username" + i,
          password = "password" + i
        });
      }
      return datas;
    }

    private static IList<TreeObejct> models;
    private static IList<TreeObejct> models2;
    private static Thread t1;
    private static Thread t2;
    static void Main(string[] args)
    {
      int count = 21;
      Console.WriteLine("生成任务数："+count+"个");
     
      Console.Read();
    }

    public static IList<TreeObejct> GetChildrens(TreeObejct node)
    {
      IList<TreeObejct> childrens = models.Where(c => c.pId == node.id.ToString()).ToList();
      foreach (var item in childrens)
      {
        item.children = GetChildrens(item);
      }
      return childrens;

    }

    public static void Recursion()
    {
      #region 递归遍历
      System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

      sw.Start();

      var mds_0 = models.Where(c => c.pId == "0");//获取顶级任务
      foreach (var item in mds_0)
      {
        item.children = GetChildrens(item);
      }
      sw.Stop();
      Console.WriteLine("----------递归遍历用时：" + sw.ElapsedMilliseconds + "----------线程名称："+t1.Name+",线程ID："+t1.ManagedThreadId);

      #endregion
    }

    private static IList<TreeObejct> models;
    private static IList<TreeObejct> models2;
    private static Thread t1;
    private static Thread t2;
    static void Main(string[] args)
    {
      int count = 1001;
      Console.WriteLine("生成任务数："+count+"个");
      models = GetData(count);
     
      t1 = new Thread(Recursion);
     
      t1.Name = "递归遍历";
      t1.Start();
    

      Console.Read();
    }

    public static void NotRecursion()
    {
      #region 非递归遍历

      System.Diagnostics.Stopwatch sw2 = new System.Diagnostics.Stopwatch();

      sw2.Start();
      Dictionary<string, TreeObejct> dtoMap = new Dictionary<string, TreeObejct>();
      foreach (var item in models)
      {
        dtoMap.Add(item.id, item);
      }
      IList<TreeObejct> result = new List<TreeObejct>();
      foreach (var item in dtoMap.Values)
      {
        if (item.pId == "0")
        {
          result.Add(item);
        }
        else
        {
          if (dtoMap.ContainsKey(item.pId))
          {
            dtoMap[item.pId].AddChilrden(item);
          }
        }


      }

      sw2.Stop();
      Console.WriteLine("----------非递归遍历用时：" + sw2.ElapsedMilliseconds + "----------线程名称：" + t2.Name + ",线程ID：" + t2.ManagedThreadId);

      #endregion
    }

    private static IList<TreeObejct> models;
    private static IList<TreeObejct> models2;
    private static Thread t1;
    private static Thread t2;
    static void Main(string[] args)
    {
      int count = 6;
      Console.WriteLine("生成任务数："+count+"个");
      models = GetData(count);
      models2 = GetData(count);
      t1 = new Thread(Recursion);
      t2 = new Thread(NotRecursion);
      t1.Name = "递归遍历";
      t2.Name = "非递归遍历";
      t1.Start();
      t2.Start();

      Console.Read();
    }