在度娘上查了大半个月的资料，最后发现每个网友分享的文章都有一定的错误（PS：大家是故意的么？）。最后是在看了一个ASP版本后知道了大概流程；看了一个存储过程实现的文章后知道了大概需要的功能；看了一个SQL语句看到了比较直观的实现；看了一个php示例后才知道最复杂的一个功能的实现。每篇文章都是网友们自己正在使用或已经测试通过的，但都很巧，恰好关键地方就有点出错，不过还是感谢这些资料了，不然我也搞不出来。
因为查了很久的资料，基本上没有可用的，所以一直不敢直接写到项目的DAL里面，就直接在控制器里面写方法进行了调试，暂时没考虑什么意外情况和效率问题，毕竟出现上述问题的前提条件是你这个功能要实现吧，呵呵，下面直接上代码（PS：有点丑，见谅）。
1 //数据初始化，反正失败了几十次，所以就在前面写了段初始化的代码，经常用到
2 cManager.DelByCondition(c => c.Id != 0);
3 Models.CmsMiee_Article_Category cate1 = new Models.CmsMiee_Article_Category() { Name = "商品", ClassLeftNum = 1, ClassRightNum = 18, ListSkin = "test", ContentSkin = "text" };
4 Models.CmsMiee_Article_Category cate2 = new Models.CmsMiee_Article_Category() { Name = "食品", ClassLeftNum = 2, ClassRightNum = 11, ListSkin = "test", ContentSkin = "text" };
5 Models.CmsMiee_Article_Category cate3 = new Models.CmsMiee_Article_Category() { Name = "肉类", ClassLeftNum = 3, ClassRightNum = 6, ListSkin = "test", ContentSkin = "text" };
6 Models.CmsMiee_Article_Category cate4 = new Models.CmsMiee_Article_Category() { Name = "猪肉", ClassLeftNum = 4, ClassRightNum = 5, ListSkin = "test", ContentSkin = "text" };
7 Models.CmsMiee_Article_Category cate5 = new Models.CmsMiee_Article_Category() { Name = "蔬菜类", ClassLeftNum = 7, ClassRightNum = 10, ListSkin = "test", ContentSkin = "text" };
8 Models.CmsMiee_Article_Category cate6 = new Models.CmsMiee_Article_Category() { Name = "白菜", ClassLeftNum = 8, ClassRightNum = 9, ListSkin = "test", ContentSkin = "text" };
9 Models.CmsMiee_Article_Category cate7 = new Models.CmsMiee_Article_Category() { Name = "电器", ClassLeftNum = 12, ClassRightNum = 17, ListSkin = "test", ContentSkin = "text" };
10 Models.CmsMiee_Article_Category cate8 = new Models.CmsMiee_Article_Category() { Name = "电视机", ClassLeftNum = 13, ClassRightNum = 14, ListSkin = "test", ContentSkin = "text" };
11 Models.CmsMiee_Article_Category cate9 = new Models.CmsMiee_Article_Category() { Name = "电冰箱", ClassLeftNum = 15, ClassRightNum = 16, ListSkin = "test", ContentSkin = "text" };
12 cManager.Add(cate1);
13 cManager.Add(cate2);
14 cManager.Add(cate3);
15 cManager.Add(cate4);
16 cManager.Add(cate5);
17 cManager.Add(cate6);
18 cManager.Add(cate7);
19 cManager.Add(cate8);
20 cManager.Add(cate9);
21 return new MvcHtmlString("OK");
22
23 //整体数据，后面涉及一些基本操作所调用的实体有些就是用的这个
24 long nodeId = 315;
25 Models.CmsMiee_Article_Category cate = cManager.GetById(nodeId);
26 //一、计算A节点的子节点数。 $num = ($AR - $AL -1)/2;
27 return Json((cate.ClassRightNum - cate.ClassLeftNum - 1) / 2, JsonRequestBehavior.AllowGet);
28
29 //二、查找A节点的所有子节点。
30 select * from tree where L > $AL and R < $AR order by L asc;
31 List<Models.CmsMiee_Article_Category> childCate = cManager.GetListByCondition(c => c.ClassLeftNum > cate.ClassLeftNum && c.ClassRightNum < cate.ClassRightNum, c => c.ClassLeftNum);
32 return Json(childCate, JsonRequestBehavior.AllowGet);
33
34 //三、查找A节点的所有父节点。
35 select * from tree where L < $AL and R > $AR order by L desc;
36 List<Models.CmsMiee_Article_Category> parentCate = cManager.GetListByCondition(c => c.ClassLeftNum < cate.ClassLeftNum && c.ClassRightNum > cate.ClassRightNum, c => c.Id);
37 string r1 = "";
38 foreach (Models.CmsMiee_Article_Category c in parentCate)
39 {
40 r1 += "," + c.Name;
41 }
42 return new MvcHtmlString(r1);
43
44 //四、在A节点下增加子节点B，B作为最后一个子节点。
45 update tree set L = L + 2 where L >= $AR;
46 update tree set R = R + 2 where R >= $AR;
47 insert into tree (name, L, R) values(‘B‘, $AR-1, $AR);
48 List<Models.CmsMiee_Article_Category> update1 = cManager.GetListByCondition(c => c.ClassLeftNum >= cate.ClassRightNum, c => c.ClassLeftNum);
49 List<Models.CmsMiee_Article_Category> update2 = cManager.GetListByCondition(c => c.ClassRightNum >= cate.ClassRightNum, c => c.ClassLeftNum);
50 foreach (Models.CmsMiee_Article_Category c in update1)
51 {
52 c.ClassLeftNum += 2;
53 cManager.Modify(c, "ClassLeftNum");
54 }
55 foreach (Models.CmsMiee_Article_Category c in update2)
56 {
57 c.ClassRightNum += 2;
58 cManager.Modify(c, "ClassRightNum");
59 }
60 Models.CmsMiee_Article_Category newClass = new Models.CmsMiee_Article_Category() { Name = "北极企鹅", ClassLeftNum = cate.ClassRightNum - 2, ClassRightNum = cate.ClassRightNum - 1, ListSkin = "test", ContentSkin = "text" };
61 cManager.Add(newClass);
62 return Json("OK", JsonRequestBehavior.AllowGet);
63
64 //五、输出节点下的所有子节点，并提供层级等信息以便生成节点树
65 List<Models.CmsMiee_Article_Category> childCate = cManager.GetListByCondition(c => c.ClassLeftNum >= cate.ClassLeftNum && c.ClassRightNum <= cate.ClassRightNum, c => c.ClassRightNum);
66 List<Models.CmsMiee_Article_Category_Layer> cateList = new List<Models.CmsMiee_Article_Category_Layer>();
67 foreach (Models.CmsMiee_Article_Category c in childCate)
68 {
69 Models.CmsMiee_Article_Category_Layer newCate = new Models.CmsMiee_Article_Category_Layer();
70 newCate.Id = c.Id;
71 newCate.Name = c.Name;
72 newCate.ClassLeftNum = c.ClassLeftNum;
73 newCate.ClassRightNum = c.ClassRightNum;
74 newCate.ListSkin = c.ListSkin;
75 newCate.ContentSkin = c.ContentSkin;
76 newCate.AddTime = c.AddTime;
77 newCate.DelTime = c.DelTime;
78 newCate.IsDeleted = c.IsDeleted;
79 newCate.Layer = cManager.GetListByCondition(c1 => c1.ClassLeftNum <= newCate.ClassLeftNum && c1.ClassRightNum >= newCate.ClassRightNum, c1 => c.ClassLeftNum).Count;
80 cateList.Add(newCate);
81 }
82 //拼接节点树
83 string tree = "";
84 foreach (Models.CmsMiee_Article_Category_Layer cl in cateList)
85 {
86 string tab = "";
87 //根据层级生成制表符
88 for (int index = 0; index < cl.Layer; index++) { tab += " "; }
89 tree += tab + cl.Name + " - 层级：" + cl.Layer + "\n";
90 }
91 MvcHtmlString result = new MvcHtmlString("<pre>" + tree + "</pre>");
92 return result;
93
94 //六、删除A节点。先要计出该节点及其所有子节点所占的左右值空间，将这些节点删掉，然后更新其它节点的左右值。
95 $num = $AR - $AL + 1;
96 delete from tree where L >= $AL and R <= $AR;
97 update tree set R = R - $num where R > $AR;
98 update tree set = L - $num where L > $AR;
99 long cateLAR = cate.ClassRightNum - cate.ClassLeftNum + 1;
100 cManager.DelByCondition(c => c.ClassLeftNum >= cate.ClassLeftNum && c.ClassRightNum <= cate.ClassRightNum);
101 List<Models.CmsMiee_Article_Category> update1 = cManager.GetListByCondition(c => c.ClassRightNum > cate.ClassRightNum, c => c.ClassRightNum);
102 List<Models.CmsMiee_Article_Category> update2 = cManager.GetListByCondition(c => c.ClassLeftNum > cate.ClassRightNum, c => c.ClassRightNum);
103 foreach (Models.CmsMiee_Article_Category c in update1)
104 {
105 c.ClassRightNum -= cateLAR;
106 cManager.Modify(c, "ClassRightNum");
107 }
108 foreach (Models.CmsMiee_Article_Category c in update2)
109 {
110 c.ClassLeftNum -= cateLAR;
111 cManager.Modify(c, "ClassLeftNum");
112 }
113 MvcHtmlString result = new MvcHtmlString("OK");
114 return result;
115
116 //七、分类的父级修改
117 //1.如果目标节点的ClassRightNum小于当前节点的ClassRightNum；并且目标节点的ClassLeftNum大于当前节点的ClassLeftNum，则返回第一个错误：
118 long selfCategoryId = 316; //要移动的节点
119 long newCategoryId = 321; //目标节点
120 Models.CmsMiee_Article_Category selfCategory = cManager.GetById(selfCategoryId);
121 Models.CmsMiee_Article_Category newCategory = cManager.GetById(newCategoryId);
122 if (selfCategory == null) return new MvcHtmlString("当前所操作的分类不存在！");
123 if (newCategory == null) return new MvcHtmlString("您选择的新分类不存在！");
124 long selfLeft = selfCategory.ClassLeftNum;
125 long selfRight = selfCategory.ClassRightNum;
126 long value = selfRight - selfLeft;
127 //取得该分类下面的所有分类，包括自身
128 List<Models.CmsMiee_Article_Category> selfCategories = cManager.GetListByCondition(c => c.ClassLeftNum >= selfLeft && c.ClassRightNum <= selfRight, c => c.Id);
129 //将所有分类的ID写入数组以便更新左右值
130 long[] selfCategoryIDS = new long[selfCategories.Count];
131 for (int index = 0; index < selfCategoryIDS.Length; index++)
132 {
133 selfCategoryIDS[index] = Convert.ToInt32(selfCategories[index].Id);
134 }
135 //将所有子类及自身的id组成字符串，逗号分隔
136 string inIDS = string.Join(",", selfCategoryIDS);
137 long parentLeft = newCategory.ClassLeftNum;
138 long parentRight = newCategory.ClassRightNum;
139 //读取新父级分类的所有父级分类及其层级
140 List<Models.CmsMiee_Article_Category> newParentCate1 = cManager.GetListByCondition(c => c.ClassLeftNum < newCategory.ClassLeftNum && c.ClassRightNum > newCategory.ClassRightNum, c => c.Id);
141 List<Models.CmsMiee_Article_Category_Layer> newParentCate = new List<Models.CmsMiee_Article_Category_Layer>();
142 foreach (Models.CmsMiee_Article_Category c in newParentCate1)
143 {
144 Models.CmsMiee_Article_Category_Layer newCate = new Models.CmsMiee_Article_Category_Layer();
145 newCate.Id = c.Id;
146 newCate.Name = c.Name;
147 newCate.ClassLeftNum = c.ClassLeftNum;
148 newCate.ClassRightNum = c.ClassRightNum;
149 newCate.ListSkin = c.ListSkin;
150 newCate.ContentSkin = c.ContentSkin;
151 newCate.AddTime = c.AddTime;
152 newCate.DelTime = c.DelTime;
153 newCate.IsDeleted = c.IsDeleted;
154 newCate.Layer = cManager.GetListByCondition(c1 => c1.ClassLeftNum <= newCate.ClassLeftNum && c1.ClassRightNum >= newCate.ClassRightNum, c1 => c.ClassLeftNum).Count;
155 newParentCate.Add(newCate);
156 }
157 //判断是前移还是后移，并更新数据库
158 if (parentRight > selfRight)
159 {
160 //后移
161 //更新左边值
162 //update CmsMiee_Article_Category set ClassLeftNum=ClassLeftNum-value-1 where ClassLeftNum>selfRight and ClassRightNum<=parentRight
163 List<Models.CmsMiee_Article_Category> tempCategories = cManager.GetListByCondition(c => c.ClassLeftNum > selfRight && c.ClassRightNum <= parentRight, c => c.Id);
164 foreach (Models.CmsMiee_Article_Category c in tempCategories)
165 {
166 c.ClassLeftNum = c.ClassLeftNum - value - 1;
167 cManager.Modify(c, "ClassLeftNum");
168 }
169 //更新新父类的父类的左边值
170 foreach (Models.CmsMiee_Article_Category_Layer c in newParentCate)
171 {
172 if (c.Layer == 1) continue;
173 c.ClassLeftNum = c.ClassLeftNum - value - 1;
174 //转换为不带层级的分类后更新到数据库中
175 Models.CmsMiee_Article_Category result = cManager.GetById(c.Id);
176 result.ClassLeftNum = c.ClassLeftNum;
177 cManager.Modify(result, "ClassLeftNum");
178 }
179 //update CmsMiee_Article_Category set ClassRightNum=ClassRightNum-value-1 where ClassRightNum>selfRight and ClassRightNum<parentRight
180 //更新右边值
181 tempCategories = cManager.GetListByCondition(c => c.ClassRightNum > selfRight && c.ClassRightNum < parentRight, c => c.Id);
182 foreach (Models.CmsMiee_Article_Category c in tempCategories)
183 {
184 c.ClassRightNum = c.ClassRightNum - value - 1;
185 cManager.Modify(c, "ClassRightNum");
186 }
187 long tempValue = parentRight - selfRight - 1;
188 tempCategories = cManager.GetListByCondition(c => selfCategoryIDS.Contains(c.Id), c => c.Id);
189 //update CmsMiee_Article_Category set ClassLeftNum=ClassLeftNum+tempValue,ClassRightNum=ClassRightNum+tempValue where Id in(selfCategoryIDS)
190 foreach (Models.CmsMiee_Article_Category c in tempCategories)
191 {
192 c.ClassLeftNum = c.ClassLeftNum + tempValue;
193 c.ClassRightNum = c.ClassRightNum + tempValue;
194 cManager.Modify(c, "ClassLeftNum", "ClassRightNum");
195 }
196 }
197 else
198 {
199 //前移
200 List<Models.CmsMiee_Article_Category> tempCategories = cManager.GetListByCondition(c => c.ClassLeftNum > parentRight && c.ClassLeftNum < selfLeft, c => c.Id);
201 //更新左边值
202 foreach (Models.CmsMiee_Article_Category c in tempCategories)
203 {
204 c.ClassLeftNum = c.ClassLeftNum + value + 1;
205 cManager.Modify(c, "ClassLeftNum");
206 }
207 //更新右边值
208 tempCategories = cManager.GetListByCondition(c => c.ClassRightNum >= parentRight && c.ClassRightNum < selfLeft, c => c.Id);
209 foreach (Models.CmsMiee_Article_Category c in tempCategories)
210 {
211 c.ClassRightNum = c.ClassRightNum + value + 1;
212 cManager.Modify(c, "ClassRightNum");
213 }
214 long tempValue = selfLeft - parentRight;
215 tempCategories = cManager.GetListByCondition(c => selfCategoryIDS.Contains(c.Id), c => c.Id);
216 foreach (Models.CmsMiee_Article_Category c in tempCategories)
217 {
218 c.ClassLeftNum = c.ClassLeftNum - tempValue;
219 c.ClassRightNum = c.ClassRightNum - tempValue;
220 cManager.Modify(c, "ClassLeftNum", "ClassRightNum");
221 }
222 }
223 return new MvcHtmlString("操作完成！");
估计是特别乱了，昨天整理了好久，总算是放到DAL里面去了，最后一个修改的功能，步骤稍微有点繁琐。为以防万一，我用的是事务，反正很简单，SaveChange你懂的》。。。
变量里面用到的cManager对象是BLL中管理分类用的类，没有什么特别，只是继承了父类的增删改查功能。
这段代码只是我测试、学习的时候用到的，后来改动了很多地方，不过关于数据库操作和无限级分类这一块，基本上没什么改动了。没这么无私，所以懒得整理了（PS：我要是像大神们那样整理，估计代码中也会“恰巧”出现一点点关键地方的错误了，呵呵）。所以需要用的朋友可以自行整理一下。
时间： 2024-10-14 09:34:23