如何在C#中显示arraylist的元素 [英] How to display the elemens of arraylist in C#

问题描述

我编写了以下代码:

Hi,
I have written the following code:

using System;
using System.Collections;

namespace ArrayList1
{
    class Program
    {
        ArrayList a1 = new ArrayList();

        static void Main(string[] args)
        {
            Program objProg = new Program();
            objProg.a1.Add(10);
            objProg.a1.Add(5.67);
            objProg.a1.Add("abcde");
            objProg.a1.Add(''c'');
            foreach(int i in objProg.a1)
            Console.WriteLine("i");
        }
    }
}

我遇到运行时异常.有身体请引导我.

Zulfi.

我尝试过的事情:

我进行了网络搜索，但是代码仍然无法正常工作.

I am getting run-time exception. Some body please guide me.

Zulfi.

What I have tried:

I did web search but still code not working.

推荐答案

尝试:

class Program
{
   static ArrayList a1 = new ArrayList();

   static void Main(string[] args)
   {
      a1.Add(10);
      a1.Add(5.67);
      a1.Add("abcde");
      a1.Add('c');
      foreach (object i in a1)
      {
         Console.WriteLine(i);
      }
   }
}

重点:
-在Main方法中创建程序类的新实例以能够访问类成员不是一个好习惯.
-a1类变量必须是静态的，才能从静态方法访问.
-在foreach循环中，不能将i声明为int，因为您的数组列表不只包含整数值.可以匹配整数，双精度型，字符串和字符的常见类型是object.
-Console.WriteLine("i");将打印字母i而不是变量i的值.

Key points:
- Creating a new instance of the program class in the Main method to be able to access a class member is not a good practice.
- a1 class variable has to be static to be accessed from a static method.
- In the foreach loop, you cannot declare i as an int since your arraylist does not hold only integer values. The common type which can match an integer, a double, a string and a character is an object.
- Console.WriteLine("i"); will print the letter i instead of the value of the variable i.

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