C# 构造tree菜单工具方法

如何构造tree数据结构，做个笔记，方便查阅，本方法是直接返回json字符串：

1private string ToMenuJson(List<Model> data, string parentId)
2        {
3            var sbJson = new StringBuilder();
4            sbJson.Append("[");
5            var entitys = data.FindAll(t => t.ParentID == parentId).ToList();
6            if (entitys.Count > 0)
7            {
8                foreach (var item in entitys)
9                {
10                    var strJson = JsonConvert.SerializeObject(item, new JsonSerializerSettings { ReferenceLoopHandling = ReferenceLoopHandling.Ignore });
11                    strJson = strJson.Insert(strJson.Length - 1, ",\"ChildNodes\":" + ToMenuJson(data, item.ID) + "");
12                    sbJson.Append(strJson + ",");
13                }
14                sbJson = sbJson.Remove(sbJson.Length - 1, 1);
15            }
16            sbJson.Append("]");
17            return sbJson.ToString();
18        }

本方法是构造tree实体,返回实体:

1/// <summary>
2        /// 绑定列表递归方法
3        /// </summary>
4        /// <param name="ddl">构造tree数据结构返回的实体</param>
5        /// <param name="menus">绑定的数据源</param>
6        /// <param name="categoryid">父级id值</param>
7        private void BindChannelType(List<ECategoryModel> ddl, List<ECategory> menus, Guid categoryid)
8        {
9            List<ECategory> filterMenu = menus.Where(w => w.ParentID == categoryid).ToList();
10
11            foreach (var m in filterMenu)
12            {
13                var mextend = new ECategoryModel
14                {
15                    ID = m.ID,
16                    ParentID = m.ParentID,
17                    CategoryName = m.CategoryName,
18                    URL = m.URL,
19                    Sort = m.Sort,
20                    IsDelete = m.IsDelete
21                };
22                ddl.Add(mextend);
23                BindChannelType(mextend.children, menus, m.ID);
24            }
25        }

构造树形数据（带空格和缩进）：

1/// <summary>
2        /// 构造树形下拉框数据结构
3        /// </summary>
4        private void Generate(List<ECategoryModel> viewList, List<ECategory> categories, Guid categoryid, int i = 0)
5        {
6            i++;
7            var filterMenu = categories.Where(w => w.ParentID == categoryid).OrderBy(w => w.Sort).ToList();
8
9            foreach (var m in filterMenu)
10            {
11                var str = ""; //父级菜单不缩进 for (var j = 1; j < i; j++) { str += HttpUtility.HtmlDecode("&nbsp;&nbsp;") + "├"; } var mextend = new ECategoryModel { ID = m.ID, ParentID = m.ParentID, CategoryName = $"{str}{m.CategoryName}", URL = m.URL, iconSkin = m.URL, Sort = m.Sort, IsDelete = m.IsDelete }; viewList.Add(mextend); Generate(viewList, categories, m.ID, i); } }

相关的实体类 ECategoryModel.cs：

1using System;
2using System.Collections.Generic;
3
4namespace MSEduPlatform.Models
5{
6    /// <summary>
7    /// ECategory表实体类
8    /// </summary>
9    public class ECategoryModel
10    {
11        /// <summary>
12        /// 菜单ID
13        /// </summary>          
14        public Guid ID { get; set; }
15
16        /// <summary>
17        /// 父级菜单ID
18        /// </summary>          
19        public Guid ParentID { get; set; }
20
21        /// <summary>
22        /// 菜单Code
23        /// </summary>          
24        public string Code { get; set; }
25
26        /// <summary>
27        /// 菜单名称
28        /// </summary>          
29        public string CategoryName { get; set; }
30
31        /// <summary>
32        /// 菜单地址
33        /// </summary>          
34        public string URL { get; set; }
35
36        /// <summary>
37        /// 菜单排序
38        /// </summary>          
39        public int Sort { get; set; }
40
41        /// <summary>
42        /// 显示状态
43        /// </summary>          
44        public int States { get; set; }
45
46        /// <summary>
47        /// 栏目权限类别
48        /// </summary>          
49        public string AuthorizationType { get; set; }
50
51        /// <summary>
52        /// 是否授权
53        /// </summary>          
54        public bool IsAuthorization { get; set; }
55
56        /// <summary>
57        /// 创建人
58        /// </summary>          
59        public Guid Creater { get; set; }
60
61        /// <summary>
62        /// 创建时间
63        /// </summary>          
64        public DateTime CreateTime { get; set; }
65
66        /// <summary>
67        /// 修改人
68        /// </summary>          
69        public Guid Modify { get; set; }
70
71        /// <summary>
72        /// 修改时间
73        /// </summary>          
74        public DateTime ModifyTime { get; set; }
75
76        /// <summary>
77        /// 是否逻辑删除
78        /// </summary>          
79        public int IsDelete { get; set; }
80
81        /// <summary>
82        /// 子数据列表
83        /// </summary>
84        public List<ECategoryModel> children = new List<ECategoryModel>();
85    }
86}