C#避免重复接口属性的代码

本文关键字：属性 代码 接口 | 更新日期: 2023-09-27 17:53:41

给定接口：

interface IVotable
{
    int TotalUpvotes { get; }
    int TotalDownvotes { get; }
    int TotalVoteScore { get; }
}

实现：

public class Comment : IVotable
{
    public int TotalUpvotes { get; private set; }
    public int TotalDownvotes { get; private set; }
    public int TotalVoteScore { get { return TotalUpvotes - TotalDownvotes + 1 ; } }
}

避免在每个类中以相同方式实现TotalVoteScore的最佳方法是什么？

C#避免重复接口属性的代码

如果你不想重新实现的只是TotalVoteScore，那么这就是方法：

public interface IVotable
{
    int TotalUpvotes { get; }
    int TotalDownvotes { get; }
    int TotalVoteScore { get; }
}
public abstract class VotableBase : IVotable
{
    public abstract int TotalUpvotes { get; protected set; }
    public abstract int TotalDownvotes { get; protected set; }
    public virtual int TotalVoteScore { get { return TotalUpvotes - TotalDownvotes + 1 ; } }
}
public class Comment : VotableBase
{
    public override int TotalUpvotes { get; protected set; }
    public override int TotalDownvotes { get; protected set; }
}

如果TotalVoteScore总是以相同的方式计算，您可以将其作为IVotable:上的扩展方法

public static int TotalVoteScore(this IVotable v) {
    return v.TotalUpvotes - v.TotalDownvotes + 1
}

public abstract class VotableBase
{
    public int TotalUpvotes { get; protected set;}
    public int TotalDownvotes { get; protected set; }
    public int TotalVoteScore { get { return TotalUpvotes - TotalDownvotes + 1 ; } }
}

那么你的派生类就不需要任何实现了——它已经继承了属性：

public class Comment : VotableBase
{
    public void DoThings()
    {
        //e.g.
        Console.WriteLine(TotalVoteScore);
    }
}

如果你想要一个接口(一个约定必须有一些具有指定签名的方法(与公共代码相结合的东西，我想解决方案是一个抽象类：

public abstract class Votable
{
    public abstract int TotalUpvotes { get; protected set; }
    public abstract int TotalDownvotes { get; protected set; }
    public virtual int TotalVoteScore { get { return TotalUpvotes - TotalDownvotes + 1; } }
}

并从该类派生：

public class Comment : Votable
{
    public override int TotalUpvotes { get; protected set; }
    public override int TotalDownvotes { get; protected set; }
}

将组合方法引入到混合中。我一点也不反对继承。但我觉得这是一个不使用它的好例子。为什么要限制这个类只能派生投票功能？我可以想象这个类有很多与"评论"更密切相关的东西，比如作者信息(排名、个人简介、头像(、格式、年龄、编辑历史等。其中一些似乎更适合作为基类。

public interface IVotable
{
    int TotalUpvotes { get; }
    int TotalDownvotes { get; }
    int TotalVoteScore { get; }
}
// shared implementation
public class VoteStatus : IVotable
{
    public int TotalUpvotes { get; private set; }
    public int TotalDownvotes { get; private set; }
    public int TotalVoteScore { get { return TotalUpvotes - TotalDownvotes + 1; } }
}
// has A...
public class Comment : IVotable
{
    // expose it?
    public IVotable VoteStatus { get; private set; }
    // allow current vote status to be injected?
    public Comment(IVotable voteStatusReference)
    {
        this.VoteStatus = voteStatusReference;
    }
    // or don't use injection?
    public Comment()
        : this(new VoteStatus())
    {
    }
    public int TotalUpvotes => this.VoteStatus.TotalUpvotes;
    public int TotalDownvotes => this.VoteStatus.TotalDownvotes;
    public int TotalVoteScore => this.VoteStatus.TotalVoteScore;
}

注意：我觉得这里的扩展方法建议也比继承好。

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