标签：图片 相同 循环引用 步骤 数据 except 一个 one dict
C# Net 树帮助类
C# Net 树节点帮助类
优点：非递归，效率可能更高
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---------------------文尾看调用方式------------------
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创建一个新的文件 TreeNodeHelper.cs 并拷贝代码：
/// <summary> /// 树节点 /// </summary> public class TreeNodeHelper { /// <summary> /// 初始化树节点 /// </summary> public TreeNodeHelper() { Children = new List<object>(); } /// <summary> /// 名称 /// </summary> public string Name { get; set; } /// <summary> /// 主键Id /// </summary> public object Id { get; set; } /// <summary> /// 父Id /// </summary> public object Pid { get; set; } /// <summary> /// 子节点 /// </summary> public List<object> Children { get; set; } } /// <summary> /// 树节点扩展 /// </summary> public static class TreeNodeExHelper { /// <summary> /// 转为树结构 /// </summary> /// <param name="treeNodes">树节点</param> /// <returns>树节点带子节点（Children）</returns> public static List<T> ToTree<T>(this List<T> treeNodes) where T : TreeNodeHelper { if (treeNodes == null || !treeNodes.Any()) return treeNodes; if (treeNodes.Any(o => o.Id == o.Pid)) throw new Exception("存在id和pid相同的数据，无限循环引用"); var group = treeNodes.GroupBy(x => x.Pid).ToDictionary(x => x.Key, s => s.ToList()); foreach (var item in treeNodes) { if (group.ContainsKey(item.Id)) { var treeNode = group[item.Id]; if (treeNode.Any(o => o.Id == item.Pid && o.Pid == item.Id)) throw new Exception("存在id和pid交叉引用(如：{Id=‘我是你‘,Pid=‘你是我‘} 和 {Id=‘你是我‘,Pid=‘我是你‘})"); item.Children.AddRange(treeNode); } } //查找顶级节点 var ids = treeNodes.Select(o => o.Id).Distinct(); var pids = treeNodes.Select(o => o.Pid).Distinct(); var c = pids.Except(ids); return group.Where(o => c.Contains(o.Key)).SelectMany(o => o.Value).ToList(); } /// <summary> /// 将指定的id节点转为树结构 /// </summary> /// <param name="treeNodes">树节点</param> /// <param name="id">id节点</param> /// <returns>树节点带子节点（Children）</returns> public static T ToTree<T>(this List<T> treeNodes, object id) where T : TreeNodeHelper { if (treeNodes == null) return null; if (!treeNodes.Any()) return treeNodes.FirstOrDefault(); if (treeNodes.Any(o => o.Id == o.Pid)) throw new Exception("存在id和pid相同的数据，无限循环引用"); var group = treeNodes.GroupBy(x => x.Pid).ToDictionary(x => x.Key, s => s.ToList()); foreach (var item in treeNodes) { if (group.ContainsKey(item.Id)) { var treeNode = group[item.Id]; if (treeNode.Any(o => o.Id == item.Pid && o.Pid == item.Id)) throw new Exception("存在id和pid交叉引用(如：{Id=‘我是你‘,Pid=‘你是我‘} 和 {Id=‘你是我‘,Pid=‘我是你‘})"); item.Children.AddRange(treeNode); } } return treeNodes.FirstOrDefault(o => o.Id == id); } }
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---------------------开始调用------------------
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1.创建一个类 Info.cs 继承 TreeNodeHelper （也可以直接使用TreeNodeHelper，忽略此步骤）
public class Info: TreeNodeHelper { /// <summary> /// 名称 /// </summary> public string MyInfo { get; set; } }
2.1 调用（方式一）
List<Info> infos = new List<Info>() { new Info (){Id="重庆",Pid="",MyInfo="a" }, new Info (){Id="渝中",Pid="重庆",MyInfo="a1" }, new Info (){Id="北碚",Pid="重庆",MyInfo="a2" }, new Info (){Id="七星岗",Pid="渝中",MyInfo="a3" }, new Info (){Id="成都",Pid="四川",MyInfo="a4" }, new Info (){Id="武侯",Pid="成都",MyInfo="a5" }, new Info (){Id="龙泉",Pid="成都",MyInfo="a6" }, }; var data = infos.ToTree();
注：json可复制粘贴到（www.json.cn）中去查看
data效果为（转为json方便查看）：
[{"MyInfo":"a","Name":null,"Id":"重庆","Pid":"","Children":[{"MyInfo":"a1","Name":null,"Id":"渝中","Pid":"重庆","Children":[{"MyInfo":"a3","Name":null,"Id":"七星岗","Pid":"渝中","Children":[]}]},{"MyInfo":"a2","Name":null,"Id":"北碚","Pid":"重庆","Children":[]}]},{"MyInfo":"a4","Name":null,"Id":"成都","Pid":"四川","Children":[{"MyInfo":"a5","Name":null,"Id":"武侯","Pid":"成都","Children":[]},{"MyInfo":"a6","Name":null,"Id":"龙泉","Pid":"成都","Children":[]}]}]
2.2 调用（方式二）
//infos数据不变...
var data = infos.ToTree("渝中");
data效果为（转为json方便查看）：
{"MyInfo":"a1","Name":null,"Id":"渝中","Pid":"重庆","Children":[{"MyInfo":"a3","Name":null,"Id":"七星岗","Pid":"渝中","Children":[]}]}
完成。
标签：图片 相同 循环引用 步骤 数据 except 一个 one dict
原文地址：https://www.cnblogs.com/ping9719/p/13278188.html
