在层次结构中循环以获取每个级别的第一个元素

Question

我有一个班级：

public class Member 
{    public string header {get;set;}    
     public List<Member> MemberCollection {get;set;} 
}

所以我有List lstMembers; 包含这样的内容：

MemberA
   |_____ header = HeadingMemberA
   |
   |_____ List<Member> = Member A.1
                    |___ Member A.2
                    |___ Member A.3

MemberB
   |_____ header = HeadingMemberB
   |
   |_____ List<Member> = Member B.1
                    |___ Member B.2
                    |___ Member B.3

所以现在我必须在每个级别获得第一名成员。

列出会员A，会员A.1，会员B和会员B.1

Answer 1

这样的事情：

List<Member> firstLevels = new List<Member>();
foreach(Member m in lstMembers)
{
   firstLevels.Add(m);
   firstLevels.Add(m.MemberCollection.First());
}

Answer 2

好吧，Member A＆amp; Member B不是他们的第一级

但是如果要获得Member A.1, Member B.1 ...

members.Select(MemberList => MemberList.MemberCollection.FirstOrDefault()).ToList();

Answer 3

如果允许使用LINQ，则可以在集合上构建表达式。使用带有order by子句的SelectMany运算符。

注意：以下代码只是为了演示这个想法并忽略任何语法/案例问题

var members = new List<Member>();
var q = members.SelectMany(m => m.MemberCollection).Orderby(o=>o.Name).FirstOrDefault()
 .ToList();