Question

初学者。我试图找到一种方法如何访问数组中的对象的属性而不总是使用“array [0]作为ClassName”，当它们不是同一类型的对象时。不需要详细的答案。你也可以建议/引导我到哪里阅读这些东西，因为也许答案会在我面前，但我不能识别它，因为我是初学者。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vezba_9_object_ecercises
{
    class Program
    {
        static void Main(string[] args)
        {

            object[] books = new object[2];

            books[0] = new SomeBooks("Book_1", "Good", 22);
            Console.WriteLine((books[4] as SomeBooks).name); // working
           // Console.WriteLine((books[4].name); // not working, how to make it work

            books[1] = new OtherBooks("Book_2", "Bad", 2);
            Console.WriteLine((books[4] as OtherBooks ).name); // working
          //  Console.WriteLine((books[4].name); // not working, how to make it work

        }
    }
    public class SomeBooks
    {
        public SomeBooks(string _name, string _likability, int _numberOfPages)
        {
            name = _name;
            likability = _likability;
            numberOfPages = _numberOfPages;
        }

        public string name { get; set; }
        public string likability { get; set; }
        public int numberOfPages { get; set; }


    }
    public class OtherBooks
    {
        public OtherBooks(string _name, string _likability, int _numberOfAuthors)
        {
            name = _name;
            likability = _likability;
            NumberOfAuthors = _numberOfAuthors;
        }

        public string name { get; set; }
        public string likability { get; set; }
        public int NumberOfAuthors { get; set; }


    }
}

Answer 1

您可以使SomeBook和OtherBook类继承自Book基类（或接口）。这将允许您将它们存储在类型为Book[]而不是object[]的数组中。您可以通过这种方式访问继承的属性，例如Name和Likability，而无需强制转换。

public class Book
{
    public string Name { get; set; }
    public string Likability { get; set; }
}

public class SomeBook : Book
{
    public int NumberOfPages { get; set; }
}

public class OtherBook : Book
{
    public int NumberOfAuthors { get; set; }
}

但是我反对这样做的必要性。问问自己这是否过度设计。你可以只有一个Book类，允许其他值为null。

public class Book
{
    public string Name { get; set; }
    public string Likability { get; set; }
    public int? NumberOfPages { get; set; }
    public int? NumberOfAuthors { get; set; }
}

Answer 2

您的数组类型必须是接口，每个元素的类型必须是继承接口的类。

public interface IBook
{
    string Name { get; set; }
    string Likability { get; set; }
}

public class SomeBook : IBook
{
    public string Name { get; set; }
    public string Likability { get; set; }
    public int NumberOfPages { get; set; }
}

public class OtherBook : IBook
{
    public string Name { get; set; }
    public string Likability { get; set; }
    public int NumberOfAuthors { get; set; }
}

public class Books
{
    public Books()
    {
        IBook[] books = new IBook[2] {
            new SomeBook(),
            new OtherBook()
        };

        for (int i = 0; i < books.Length; i++)
        {
            switch (books[i].GetType().Name)
            {
                case "SomeBook":
                    int numberOfPages = ((SomeBook)books[i]).NumberOfPages;
                    break;

                case "OtherBook":
                    int numberOfAuthors = ((OtherBook)books[i]).NumberOfAuthors;
                    break;
            }
        }
    }
}

C＃制作不同类型对象的数组

2 个答案: