c# - 获取 List 及其嵌套列表属性的所有值

Question

今天早上我突然想到这似乎是一个很容易解决的问题。我想将列表的所有值写入我的控制台。在这种情况下，列表包含列表成员。一段时间以来，我一直在寻找解决方案，但找不到。

我已经做到了。

tl.ForEach(tradelane =>
        {
            row = "";

            foreach(PropertyInfo pi in typeof(coTradeLane).GetProperties())
            {
                Type T = pi.PropertyType;

                if (T.IsGenericType && T.GetGenericTypeDefinition() == typeof(List<>))
                {
                    foreach(PropertyInfo piList in tradelane.GetType().GetProperties())
                    {

                            // Select the nested list and loop through each member..

                    }
                    continue;
                }

                var val = pi.GetValue(tradelane);
                if (val != null) row += val.ToString() + " \t ";
                else row += " \t \t ";
            }
            Console.WriteLine(row);
        });

Answer 1

我不完全确定你想要什么，但这个递归解决方案可能会帮助你。我有点作弊，因为我正在寻找 IList而不是 List<T>以简化代码。

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace Demo
{
    // This type contains two properties.
    // One is a plain List<Double>, the other is a type that itself contains Lists.

    public sealed class Container
    {
        public List<double> Doubles { get; set; }

        public Lists Lists { get; set; }
    }

    // This type contains two Lists.

    public sealed class Lists
    {
        public List<string> Strings { get; set; }
        public List<int> Ints { get; set; }
    }

    public static class Program
    {
        private static void Main()
        {
            var lists = new Lists
            {
                Strings = new List<string> {"A", "B", "C"}, 
                Ints = new List<int> {1, 2, 3, 4, 5}
            };

            var container = new Container
            {
                Doubles = new List<double> {1.1, 2.2, 3.3, 4.4},
                Lists = lists
            };

            var items = FlattenLists(container);

            // This prints:
            //
            // 1.1
            // 2.2
            // 3.3
            // 4.4
            // A
            // B
            // C
            // 1
            // 2
            // 3
            // 4
            // 5

            foreach (var item in items)
                Console.WriteLine(item);
        }

        // This recursively looks for all IList properties in the specified object and its subproperties.
        // It returns each element of any IList that it finds.

        public static IEnumerable<object> FlattenLists(object container)
        {
            foreach (var pi in container.GetType().GetProperties().Where(p => p.GetMethod.GetParameters().Length == 0))
            {
                var prop = pi.GetValue(container);

                if (typeof(IList).IsAssignableFrom(pi.PropertyType))
                {
                    foreach (var item in (IList) prop)
                        yield return item;
                }

                foreach (var item in FlattenLists(prop))
                    yield return item;
            }
        }
    }
}

不过我不确定这有多大用处，因为您只是得到一个扁平化列表 object不知道与它们相关联的属性。但是，您可以修改 FlattenLists()返回更多信息，而不仅仅是对象。