Lambda 递归获取所有子节点

实体结构：

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public class Sys_Menu { public string MenuCode { get; set; }   public string MenuDesc { get; set; }   public string ParentCode { get; set; } }

　　

 

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/// <summary>         /// 获取current所有子级         /// </summary>         /// <param name="list"></param>         /// <param name="current"></param>         /// <returns></returns>           public static List<Sys_Menu> GetChildren(List<Sys_Menu> list, Sys_Menu current)         {             var query = list.Where(x => x.ParentCode == current.MenuCode).ToList();             return query.Concat(query.SelectMany(t => GetChildren(list, t))).ToList();           }           /// <summary>         /// 获取current的所有父级         /// </summary>         /// <param name="list"></param>         /// <param name="current"></param>         /// <returns></returns>         public static List<Sys_Menu> GetParents(List<Sys_Menu> list, Sys_Menu current)         {             var query = list.Where(x => x.MenuCode == current.ParentCode).ToList();             return query.Concat(query.SelectMany(t => GetParents(list, t))).ToList();           }

　　测试代码：

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Sys_Menu menu = new Sys_Menu { MenuCode = "01", MenuDesc = "根节点", ParentCode = null };                   Sys_Menu menu1 = new Sys_Menu { MenuCode = "02", MenuDesc = "系统管理", ParentCode = "01" };             Sys_Menu menu2 = new Sys_Menu { MenuCode = "03", MenuDesc = "用户管理", ParentCode = "02" };             Sys_Menu menu3 = new Sys_Menu { MenuCode = "04", MenuDesc = "角色管理", ParentCode = "02" };               Sys_Menu menu4 = new Sys_Menu { MenuCode = "05", MenuDesc = "基础数据", ParentCode = "01" };                   List<Sys_Menu> menuList = new List<Sys_Menu>();             menuList.Add(menu);             menuList.Add(menu1);             menuList.Add(menu2);             menuList.Add(menu3);             menuList.Add(menu4);               Expression<Func<Sys_Menu, Sys_Menu, bool>> tt = (x, y) => x.MenuCode == y.ParentCode;               List<Sys_Menu> parents = new List<Sys_Menu>();             TreeUtil.GetParents(menuList, menu3, "MenuCode","ParentCode", parents);               List<Sys_Menu> children = new List<Sys_Menu>();             TreeUtil.GetChildren(menuList, menu1, "MenuCode", "ParentCode", children);               var mm = GetChildren(menuList, menu);               var mm1 = GetParents(menuList, menu3);               Console.ReadKey();