这是让 C# 类共享对象的有效方法吗？

Question

我有一组要序列化为 xml 文件的类。这些类共享一些数据。我一直在研究一些类似的问题，但似乎没有一个问题是我想要的。基本上，对我来说最好的方法是创建一个基类，其中包含一个保存数据的对象。然后我可以通过这个对象将封装在一个对象中的数据传递给派生类。这样我就不必在类中定义字段来共享对该共享对象的引用。我已经编写了这种方法的简化示例，它似乎按我预期的方式工作。

我的问题是实现这一目标的最佳方式吗？有没有更好的办法？

谢谢！

示例：

using System;
using System.Collections.Generic;
using System.IO;

namespace test
{
    public class SharedProperties
    {
        public int x = 0;
    }

    public class BaseA
    {
        private SharedProperties s;

        protected BaseA(SharedProperties sparm)
        {
            s = sparm;
        }

        public int spx { get => s.x ; set => s.x = value; }
    }

    public class Derived1 : BaseA
    {
        public Derived1() : base(null) { }

        public Derived1(SharedProperties x) : base(x) { }

    }

    public class Derived2 : BaseA
    {
        public Derived2() : base(null) { }

        public Derived2(SharedProperties x) : base(x) { }

    }

    internal class Program
    {
        private static void Main(string[] args)
        {
            SharedProperties sp = new SharedProperties();

            Derived1 d1 = new Derived1(sp);

            Derived2 d2 = new Derived2(sp);

            d1.spx = 1;

            Console.WriteLine("d2.spx = {0}", d2.spx);

            d2.spx = 2;

            Console.WriteLine("d1.spx = {0}", d1.spx);

        }
    }
}

Answer 1

Python 之禅说，

显式优于隐式

即使它不是 Python，这条规则也适用于此。当您传递相同的SharedProperties 参数时，在任何类中更改spx 并不明显会影响其他类。这是调试的噩梦，很难阅读和支持。如果您需要共享属性，请创建单独的类/服务，将其注入您的实例并使用它修改参数，而不是使用 spx 属性隐式修改它。

Answer 2

抱歉，稍微修改了您的代码，使其不再那么抽象。

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

public class Program
{
    public class Color
    {
        public string Name { get; set; } = "blue";
    }

    public abstract class Cup
    {
        protected Color Color { get; private set; }
        protected Cup(Color color)
        {
            Color = color;
        }

        public string ColorName 
        { 
            get => Color.Name; 

            /// ATTENTION:
            /// Try to avoid setting properties of shared properties
            /// this will lead to errors and is very difficult to 
            /// find in debugging or searching for potential errors
            set => Color.Name = value; 
        }
    }

    public class TeaCup : Cup
    {
        public TeaCup() : base(null) { }
        public TeaCup(Color color) : base(color) { }
    }

    public class CoffeeCup : Cup
    {
        public CoffeeCup() : base(null) { }
        public CoffeeCup(Color color) : base(color) { }
    }

    private static void Main(string[] args)
    {
        var color = new Color();
        var cup1 = new TeaCup(color);
        var cup2 = new CoffeeCup(color);

        Console.WriteLine("color = {0}", color.Name);

        cup1.ColorName = "red";
        Console.WriteLine("cup1.ColorName = {0}", cup1.ColorName);
        Console.WriteLine("cup2.ColorName = {0}", cup2.ColorName);

        cup2.ColorName = "green";
        Console.WriteLine("cup1.ColorName = {0}", cup1.ColorName);
        Console.WriteLine("cup2.ColorName = {0}", cup2.ColorName);
    }
}

如果您现在更改Color.Name，它会在使用相同color 创建的每个Cup 实现中更改。见代码中的注释。

我认为最好直接在 Color 实例上显式设置 Color.Name 而不是由另一个包装实例 (Cup) 转发。

First approch: .netfiddle link to try it out

因此，在我看来，更好的方法是注入类似于 SharedProperties (Color) 提供程序/服务的东西

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

public class Program
{
    public interface IColorProvider
    {
        string GetName();
    }

    public class ColorProvider : IColorProvider
    {
        private string _name = "blue";
        public void SetName(string name) { _name = name; }
        public string GetName() { return _name; }
    }

    public abstract class Cup
    {
        private readonly IColorProvider _colorProvider;
        protected Cup(IColorProvider colorProvider)
        {
            _colorProvider = colorProvider;
        }

        public string ColorName { 
            get => _colorProvider.GetName(); 
        }
    }

    public class TeaCup : Cup
    {
        public TeaCup() : base(null) { }
        public TeaCup(IColorProvider colorProvider) : base(colorProvider) { }
    }

    public class CoffeeCup : Cup
    {
        public CoffeeCup() : base(null) { }
        public CoffeeCup(IColorProvider colorProvider) : base(colorProvider) { }
    }

    private static void Main(string[] args)
    {
        var colorProvider = new ColorProvider();
        var cup1 = new TeaCup(colorProvider);
        var cup2 = new CoffeeCup(colorProvider);

        Console.WriteLine("color = {0}", colorProvider.GetName());

        colorProvider.SetName( "red");
        Console.WriteLine("cup1.ColorName = {0}", cup1.ColorName);
        Console.WriteLine("cup2.ColorName = {0}", cup2.ColorName);

        colorProvider.SetName( "green");
        Console.WriteLine("cup1.ColorName = {0}", cup1.ColorName);
        Console.WriteLine("cup2.ColorName = {0}", cup2.ColorName);
    }
}

Second approch: .netfiddle link to try it out