C#構建樹形資料結構

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轉自：https://www.jb51.net/article/125747.htm

樹形結構：最近在做任務管理，任務可以無限派生子任務且沒有數量限制，前端採用Easyui的Treegrid樹形展示控制項。

a.JSON資料格式：

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

　　

b.定義實體必要欄位

為了Tree結構的通用性，我們可以定義一個抽象的公用實體TreeObject以保證後續涉及到的List<T>轉化樹形JSON

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; namespace MyTree.Abs{  public 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);    }  }}

　　c.實際所需實體TreeModel讓它繼承TreeObject,這樣對於id,pId,name,children我們就可以適用於其它實體了，這也相當於我們代碼的特殊約定：

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; }  }}

　　

2、遞迴遍曆

擷取全部任務並轉化為樹形

擷取全部任務轉化為樹形是比較簡單的，我們首先擷取到pId=0的頂級資料(即不存在父級的任務),我們通過頂級任務依次遞迴遍曆它們的子節點。

 /      //遞迴擷取所有樹結構的資料        public  IList<TreeObject> GetData()        {            List<TreeObject> nodes = _context.Node.Where(x => x.parent_node_id == 0).Select(x=>new TreeObject { id=x.id,pId=x.parent_node_id,name=x.name}).ToList();            foreach(TreeObject item in nodes)            {                item.children = GetChildrens(item);            }            return nodes;        }        //遞迴擷取子節點        public IList<TreeObject> GetChildrens(TreeObject node)        {            IList<TreeObject> childrens = _context.Node.Where(c => c.parent_node_id == node.id).Select(x => new TreeObject { id = x.id, pId = x.parent_node_id, name = x.name }).ToList();            foreach (TreeObject item in childrens)            {                item.children = GetChildrens(item);            }            return childrens;        }

3、非遞迴遍曆

非遞迴遍曆在操作中不需要遞迴方法的參與即可實現Tree的拼接

對於以上的代碼，我們不需要修改，只需要定義一個非遞迴遍曆方法NotRecursion：

public static void NotRecursion(){  #region 非遞迴遍曆   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("----------非遞迴遍曆用時：" + sw2.ElapsedMilliseconds + "----------線程名稱：" + t2.Name + ",線程ID：" + t2.ManagedThreadId);   #endregion

　　main.cs

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("產生任務數："+count+"個");  models = GetData(count);  models2 = GetData(count);  t1 = new Thread(Recursion);  t2 = new Thread(NotRecursion);  t1.Name = "遞迴遍曆";  t2.Name = "非遞迴遍曆";  t1.Start();  t2.Start();   Console.Read();}

　　

C#構建樹形資料結構