C# 使用递归获取所有下属、所有子部门……

本例中获取的是所有的晚辈！首先定义家庭成员类：

    public class FamilyMember
    {
        /// <summary>
        /// 身份
        /// </summary>
        public string identity { get; set; }
        public int level { get; set; }
        /// <summary>
        /// 父亲
        /// </summary>
        public string father { get; set; }
    }

然后，定义递归方法：

        /// <summary>
        /// 递归获取晚辈
        /// </summary>
        /// <param name="members"></param>
        /// <param name="m"></param>
        /// <returns></returns>
        public static List<FamilyMember> GetYoungers(List<FamilyMember> members, FamilyMember m)
        {
            var result = new List<FamilyMember>();

            //获取子女
            var subordinate = members.Where(e => e.father == m.identity).ToList();

            //如果存在子女
            if (subordinate != null)
            {
                result.AddRange(subordinate);
                foreach (var subo in subordinate)
                {
                    result.AddRange(GetYoungers(members, subo));
                }
            }

            return result;
        }

　　方法解释：

　　　　首先，既然是递归，肯定是自己调用自己；

　　　　然后，在方法体内部：

　　　　　　　　既然要获取所有的下属（晚辈），首先要获取自己的直属下属，并将结果存入“下属”集合中；

　　　　　　　　然后遍历所有直接下属，通过递归，调用方法本身，获取 “直属下属的直属下属”，同样存入“下属”集合中；

　　　　　　　　最后，返回“下属”集合。

递归测试：

        /// <summary>
        /// 测试递归
        /// </summary>
        public static void CheckRecursion()
        {
            List<FamilyMember> list = new List<FamilyMember>
            {
                new FamilyMember{ identity = "爷爷", level = 1, father = ""},
                new FamilyMember{ identity = "爸爸", level = 2, father = "爷爷"},
                new FamilyMember{ identity = "叔叔", level = 2, father = "爷爷"},
                new FamilyMember{ identity = "自己", level = 3, father = "爸爸"},
                new FamilyMember{ identity = "弟弟", level = 3, father = "爸爸"},
                new FamilyMember{ identity = "堂兄", level = 3, father = "叔叔"},
                new FamilyMember{ identity = "堂弟", level = 3, father = "叔叔"},
                new FamilyMember{ identity = "儿子", level = 4, father = "自己"},
                new FamilyMember{ identity = "女儿", level = 4, father = "自己"},
                new FamilyMember{ identity = "侄子", level = 4, father = "弟弟"},
                new FamilyMember{ identity = "侄女", level = 4, father = "弟弟"}
            };

            var self = new FamilyMember { identity = "爷爷", level = 1, father = "" };

            var youngers = GetYoungers(list, self).OrderBy(p => p.level).ToList();
            if(youngers != null)
            {
                foreach(var p in youngers)
                {
                    Console.WriteLine(p.identity);
                }
            }
        }

　　调用该方法即可查看效果：