c# - 由于保护级别，无法在同一命名空间中为公共(public)类使用构造函数？

Question

我目前正在尝试映射很多 channel ，因此为了方便起见，制作了一个可以包含 channel 属性的类和一个字典，它将 ID 映射到 channel 。字典在一个类中， channel 定义在它们自己的类中，但在同一个命名空间中。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ParentId = System.String;
using ChildIds = System.Collections.Generic.List<int>;
using ChannelName = System.String;
using CatalogEntry = System.Tuple<System.String, System.Collections.Generic.List<int>, System.String>;


namespace example
{
    public class ChannelHandler
    {
        public ChannelName channelname { get; set; }
        public ParentId parentid { get; set; }
        public ChildIds list_of_childs { get; set; }
        public int id;

        ChannelHandler(ChannelName name, int id)
        {
            this.channelname = name;
            this.id = id;
        }

        ChannelHandler(ChannelName name, int id, ParentId parentid)
        {
            this.channelname = name;
            this.id = id;
            this.parentid = parentid;
        }

    }

    public class Class1
    {
        private Dictionary<int?, ChannelHandler> dictionary = new Dictionary<int?, ChannelHandler>();
        public void inser_into_dictionary(string path)
        {
            string[] separatingChars = { "  " };
            string[] splittedPath = path.Split(separatingChars, StringSplitOptions.RemoveEmptyEntries);
            int parentId = 0;
            ChannelName parentName = string.Empty;
            foreach (string channel_id in splittedPath)
            {

                ChannelName name = channel_id.Split('_').ElementAt(0);
                string id = channel_id.Split('_').ElementAt(1);
                int int_id = 0;
                if (int.TryParse(id, out int_id))
                {
                    int_id = int.Parse(id);
                }

                Tuple<string, int> pair_of_channel_and_id = new Tuple<string, int>(name, int_id);
                if (this.dictionary.ContainsKey(int_id))
                {
                    // Key exist, meaning this is a parent. 
                    // Child entry has to be updated. 
                    parentId = int_id;
                    parentName = name;
                }
                else
                {
                    if (parentId == 0)
                    {
                        ChannelHandler channel = new ChannelHandler(name, int_id); //ChannelHandler.ChannelHandler is inaccesible due to protection level. 
                        this.dictionary.Add(int_id, channel);

                    }
                }
            }
        }
    }
}

我似乎无法创建对象 channel 因为该类的构造函数似乎由于保护级别而无法访问？但是什么保护级别——一切都是公开的？

Answer 1

它可能看起来像:

public class ChannelHandler
{
    public ChannelName ChannelName { get; set; }
    public ParentId ParentId { get; set; }
    public List<ChildId> ChildIds { get; set; }
    public int Id;

    public ChannelHandler(ChannelName name, int id)
    {
        ChannelName = name;
        Id = id;
    }

    public ChannelHandler(ChannelName name, int id, ParentId parentid)
    {
        ChannelName = name;
        Id = id;
        ParentId = parentid;
    }

默认情况下，类的任何元素的访问级别都是private。您需要将构造函数设为 public 或 internal 以便类本身可以从外部访问。如果你看这篇文章here它解释了访问修饰符如何影响代码的可访问性级别。

我所做的另一项更改是更改您的成员的大小写以满足 c# 编码约定。参见 here