为什么将项目写入控制台仅写入名称空间和类名称，而不写入数据？ [英] Why writing items to console writes only namespace and class name instead of data?

问题描述

对于大多数人（熟练的程序员）来说，标题听起来似乎不太好，但是我正在学习C＃基础知识的第三周，我无法弄清楚如何解决下一个任务。
我将为一堆城市存储一些温度，首先要求用户输入cityName，然后再询问该城市的实际温度。所有这些东西都应该保存在列表中，并且我将使用Class和Constructor。
当我尝试打印结果（使用foreach）时，它打印出我的名称空间的名称和类的名称，例如 Task_5.City。
我的代码有什么问题：

Probably the title doesn't sound very well for most of you guys (skilled programmers), but I'm on my 3rd week of learning C# fundamentals and I cant figure it out how to solve the next task. I shall store some temperatures for a bunch of cities, asking a user for a cityName first and then for the actual temp in that city. All this stuff should be saved in a list<> and I shall use Class and Constructor. When I try to print out the result (using foreach) it prints out the name of my namespace and the name of my class like "Task_5.City" Whats wrong with my code:

public class City //class
{
    public string CityName { get; set; }
    public int Temperature { get; set; }

    public City(string name, int temp)//konstruktor 
    {
        this.CityName = name;
        this.Temperature = temp;
    }

}

class Program
{
    static void Main(string[] args)
    {
        var cityList = new List<City>(); 

        Console.WriteLine("What is your city?");
        string cityName = Console.ReadLine();
        Console.WriteLine("What temperature for this city?");
        int temp = Convert.ToInt32(Console.ReadLine());

        City myCity = new City(cityName, temp);
        cityList.Add(myCity);


        foreach (var item in cityList)
        {
            Console.WriteLine(item);
        }

        Console.ReadLine();

    }
}

推荐答案

您正在将对象传递给 Console.WriteLine（item），而不是传递字符串。 Console.WriteLine 调用该对象的 ToString（）方法，默认情况下返回名称空间+类名。您可以像下面这样覆盖此行为：

You are passing object to the Console.WriteLine(item) instead of passing the string. Console.WriteLine invokes ToString() method of that object that by default returns namespace+class name. You can override this behavior like next:

    public class City //class
    {
        public string CityName { get; set; }
        public int Temperature { get; set; }

        public City(string name, int temp)//konstruktor 
        {
            this.CityName = name;
            this.Temperature = temp;
        }

        public override string ToString()
        {
            return string.Format("{0} {1}", CityName, Temperature);
        }

    }

或者您可以使用另一个重载 WriteLine 方法：

Or you can use another overload of WriteLine method:

Console.WriteLine("{0} {1}", item.CityName, item.Temperature);

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