为什么需要覆盖ToString? [英] Why do I need to override ToString?

问题描述

我是c#编程的初学者，最近开始攻读学士学位.我想说的是，我是新来的.

I'm a beginner to c# programming and recently started working on a bachelors degree. What I'm trying to say is, I'm new.

我已标记出发生问题的地方.问题是我根本不明白为什么我需要在代码中放置重写.

I have marked the place where I have the problem. The problem is that I don't understand why I need to put override in the code at all.

类型对象有2个var(第一个和其余个).

There is 2 var of the type object (first and rest).

public Pair()
  {
    first = rest = null;
  }

public Pair(Object o)
  {
    first = o;
    rest = null;
  }

public Object First()
  {
    return(first);
  }
public Object Rest()
  {
    return(rest);
  }

public Pair Connect(Object o)
  {
    rest = o;
    return(this);
  }

//这是我不理解的替代字符串ToString".为什么我需要覆盖它?

//Here is the "override string ToString" I don't understand. Why do I need to override this?

 public override string ToString()
  {
    string output = "(";
Pair p = this;
while (p != null) {
      if (p.First() == null)
        output += "NULL";
      else
        output += p.First().ToString();
      if (p.Rest() is Pair)
    p = (Pair)(p.Rest());
      else {
    if (p.Rest() != null)
          output += " . " + rest.ToString();
    break;
  }
  output += " ";
}
    output += ")";
    return(output);
}

推荐答案

只要有对象，并且想更改将其表示为字符串的方式，就可以override ToString方法.

You override the ToString method whenever you have an object and you would like to change the way it is represented as a string.

通常对格式设置选项执行此操作，这样，当您在控制台上打印项目时，您可以控制如何向查看对象的人显示它们.

This is usually done for formatting options, so that when you print items to console you have control over how they are displayed to who ever is viewing them.

例如，给定此类:

    class Person
    {
        public int Age { get; set; }
        public string Name { get; set; }
    }

将Person类的实例打印到控制台将产生:namespace+classname，从可读性的角度来看，这是不理想的.

Printing an instance of the Person class to console would yield: namespace+classname, which from a readability point of view is not ideal.

将课程更改为此:

    class Person
    {
        public int Age { get; set; }
        public string Name { get; set; }

        public override string ToString()
        {
            return String.Format("Name: {0} Age: {1}.", this.Name, this.Age);
        }
    }

收益率:Name: ... Age: ...其中的椭圆表示所提供的值.这比以前的方案更具可读性.

Yields: Name: ... Age: ... where the ellipses denote the values provided. This is more readable than the previous scenario.

这篇关于为什么需要覆盖ToString?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！