c# - Linq 递归搜索节点

Question

试图获得所有List<Node>()的最后列表那不是空的。如何对子节点执行此操作？

public class Node
{
    public string Name { get; set; }

    public List<Node> Nodes { get; set; }
}

public class Program
{
    static void Main(string[] args)
    {
        List<Node> Items = new List<Node>();
        Items.Add(new Node { Name = "Test0" });
        Items.Add(new Node { Name = "Test1" });
        Items.Add(new Node { Name = "Test2" });
        Items.Add(new Node { Name = "Test3" });
        Items.Add(new Node { Name = "Test4" });
        Items.Add(new Node { Name = "Test5" });
        Items.Add(new Node
        {
            Name = "Test6",
            Nodes = new List<Node>
            {
                new Node
                {
                    Name = "Test6.1",
                    Nodes = new List<Node>
                    {
                        new Node
                        {
                            Name = "Test6.1.1", Nodes = new List<Node>()
                        }
                    }
                },

            }
        });
        Items.Add(new Node { Name = "Test7", Nodes = new List<Node> { } });
        Items.Add(new Node { Name = "Test8", Nodes = new List<Node> { } });

        var NotNullNodes = Items.SelectMany(m => m.Nodes);
    }
}

Answer 1

另一个 linq 递归解决方案:

public static IEnumerable<Node> GetAllNodes( Node root )
{
    if( root == null )
    {
        yield break;
    }

    yield return root;

    if ( root.Nodes == null )
    {
        yield break;
    }

    foreach ( Node descendant in root.Nodes.SelectMany( GetAllNodes ) )
    {
        yield return descendant;
    }
}

像这样使用:

Items.SelectMany( GetAllNodes )