我在这个方法c#中返回什么

Question

我正在尝试返回歌曲名称、艺术家姓名和销量。唯一似乎在返回中编译的是方法名称，它不可能是正确的，因为它只会导致它成为一个无限循环。

同样在循环中，如何更改 tryparse 使其也不接受负数？

代码如下

namespace Songs
{
    class Program
    {
        static void Main(string[] args)
        {
            object [] ArrayOfSongs;
            ArrayOfSongs = new object[4];

            for (int i = 4; i < ArrayOfSongs.Length; i++)
            {
                ArrayOfSongs[i] = InputSongDetails();
                var store = InputSongDetails();
            }

            Console.WriteLine("Enter an artists name, or press return for all artists");
        }

        static Song InputSongDetails()
        {
            Console.WriteLine("What is the name of your song");
            string name = Console.ReadLine();

            Console.WriteLine("What is the artists name");
            string artist = Console.ReadLine();

            int records;
            Console.WriteLine("How many records did it sell");
            while (!int.TryParse(Console.ReadLine(), out records))
            {
                Console.WriteLine("That is not valid please enter a number");
            }
            string returns = $"Your song is{name}, the artists name is {artist} and it sold {records} records";
            return InputSongDetails();
        }
    }
}

这是我的歌曲课

namespace Songs

{ 班歌 { 字符串名称； 弦乐艺术家； int 副本已售出；

    public Song(string name, string artist, int copiesSold)
    {
        this.name = name;
        this.artist = artist;
        this.copiesSold = copiesSold;
    }

    public Song()
    {
    }

    public string GetArtist()
    {
        return artist;
    }

    public string GetDetails()
    {
        return $"Name: {name} Artist: {artist} Copies Sold: {copiesSold},";
    }

    public string GetCertification()
    {
        if (copiesSold<200000)
        {
            return null;
        }
        if (copiesSold<400000)
        {
            return "Silver";
        }
        if (copiesSold<600000)
        {
            return "gold";
        }
        return "Platinum";  
    }
}

}

Answer 1

根据您的方法签名，您将返回类似于 Song 的内容：

static Song InputSongDetails()

理想情况下，您将在某处定义一个名为 Song 的类，如下所示：

class Song
{
    public string Name { get; set; }
    public string Artist { get; set; }
    public int Records { get; set; }
}

所以，你的回报应该是这样的：

return new Song
{
    Name = name,
    Artist = artist,
    Records = records
};

对于您的循环，只需在 while 子句中添加一个附加条件：

while (!int.TryParse(Console.ReadLine(), out records) || records < 0)

更新：

根据您新发现的Song 类，只需使用第一个构造函数返回一个新实例：

return new Song(name, artist, records);

Answer 2

编译器不会阻止您创建无限循环。我认为你想要返回的是一个新的Song 对象（猜测属性名称）：

  return new Song() {
      Name = name,
      Artist = artist,
      Records = records
  };

同样在循环中，如何更改 tryparse 使其也不接受负数？

将tryparse 放入while 循环中，如果根据您想要的任何条件解析的值“有效”，则该循环将退出。

Answer 3

我想你有一个像这样的 Song 类

public class Song {
    public string Name {get; set; }
    public string Artist {get;set; }
    public int Records {get;set; }
}

然后你必须在你的 InputSongDetails 方法中返回一个新的 Song 对象

static Song InputSongDetails()
{
    var song = new Song();
    Console.WriteLine("What is the name of your song");
    song.Name = Console.ReadLine();

    Console.WriteLine("What is the artists name");
    song.Artist = Console.ReadLine();

    int records;
    Console.WriteLine("How many records did it sell");
    while (!int.TryParse(Console.ReadLine(), out records))
    {
        Console.WriteLine("That is not valid please enter a number");
    }
    song.Records = records;
    string returns = String.Format("Your song is{0}, the artists name is {1} and it sold {2} records", song.Name, song.Artist, song.Records);

    return song;
}   

Answer 4

更新为使用 op 的类

using System;


namespace Songs
{
class Program
{
    static void Main(string[] args)
    {
        Song[] ArrayOfSongs = new Song[4];

        for (var i = 0; i < ArrayOfSongs.Length; i++)
        {

            ArrayOfSongs[i] = InputSongDetails();

        }

        Console.ReadLine();
    }

    static Song InputSongDetails()
    {
        //Song returnObj = new ExpandoObject();
        Console.WriteLine("Enter an artists name, or press return for all artists");
        Console.WriteLine("What is the name of your song");
        string name = Console.ReadLine();
       // returnObj.name = name;
        Console.WriteLine("What is the artists name");
        string artist = Console.ReadLine();
        //returnObj.artist = artist;
        Console.WriteLine("How many records did it sell");
        string recordsStr = Console.ReadLine();
        int records;
        while (!Int32.TryParse(recordsStr, out records) || records < 0)
        {
            Console.WriteLine("try again");
            recordsStr = Console.ReadLine();
        }
        //returnObj.records = records;
        Console.WriteLine($"Your song is{name}, the artists name is {artist} and it sold {records.ToString()} records");
        return new Song(name,artist,records);

    }
}

 class Song
{
    string name; string artist; int copiesSold;

    public Song(string name, string artist, int copiesSold)
    {
        this.name = name;
        this.artist = artist;
        this.copiesSold = copiesSold;
    }

    public Song()
    {
    }

    public string GetArtist()
    {
        return artist;
    }

    public string GetDetails()
    {
        return $"Name: {name} Artist: {artist} Copies Sold: {copiesSold},";
    }

    public string GetCertification()
    {
        if (copiesSold < 200000)
        {
            return null;
        }
        if (copiesSold < 400000)
        {
            return "Silver";
        }
        if (copiesSold < 600000)
        {
            return "gold";
        }
        return "Platinum";
    }
}

}