以下示例代码中 AttemptController 中的静态字段是什么意思？答案

【问题标题】：What is the meaning of the static field in AttemptController in following sample code ?以下示例代码中 AttemptController 中的静态字段是什么意思？
【发布时间】：2019-04-27 18:08:34
【问题描述】：

我是 C# 的新手，正在尝试学习静态关键字。我不明白为什么我们需要两次初始化静态字段。据我了解，静态字段在程序执行期间保留该值。

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

        AttemptController Obj = new AttemptController(3, 2);
        Console.WriteLine("Maximum:   {0}", AttemptController.MaxAttempts);
        Console.WriteLine("Warning:   {0}", AttemptController.WarningAttempts);
        Console.WriteLine("Threshold: {0}", AttemptController.Threshold);

        AttemptController Obj1 = new AttemptController(7, 5);
        Console.WriteLine("Maximum:   {0}", AttemptController.MaxAttempts);
        Console.WriteLine("Warning:   {0}", AttemptController.WarningAttempts);
        Console.WriteLine("Threshold: {0}", AttemptController.Threshold);
        Console.ReadLine();
    }

    class AttemptController
    {
        internal static int MaxAttempts;
        internal static int WarningAttempts;
        internal static int Threshold;

        public AttemptController(int a, int b)
        {
            MaxAttempts = a;
            WarningAttempts = b;
            Threshold = MaxAttempts - WarningAttempts;
        }
    }
}

【问题讨论】：

尝试将AttemptController类设为静态
AttemptController??这是 MVC 应用程序吗？如果是，那么拥有这些静态字段是无用的

标签： c# oop static

【解决方案1】：

所以提出了一些更改：

将类设为静态
去掉构造函数，因为静态类不能有实例构造函数。

添加一个名为 init 的新方法，仅用于演示目的。

using System;

namespace ConsoleApp4
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            AttemptController.Init(3, 2);
            Console.WriteLine("Maximum:   {0}", AttemptController.MaxAttempts);
            Console.WriteLine("Warning:   {0}", AttemptController.WarningAttempts);
            Console.WriteLine("Threshold: {0}", AttemptController.Threshold);

            AttemptController.Init(7, 5);
            Console.WriteLine("Maximum:   {0}", AttemptController.MaxAttempts);
            Console.WriteLine("Warning:   {0}", AttemptController.WarningAttempts);
            Console.WriteLine("Threshold: {0}", AttemptController.Threshold);
            Console.ReadLine();
    }
}

    public static class AttemptController
    {
        internal static int MaxAttempts;
        internal static int WarningAttempts;
        internal static int Threshold;



        public static void Init(int a, int b)
        {
            MaxAttempts = MaxAttempts + a;
            WarningAttempts = WarningAttempts + b;
            Threshold = MaxAttempts - WarningAttempts;
        }
    }
}

【讨论】：

【解决方案2】：

因为你在构造方法中设置了MaxAttempts,WarningAttempts,Threshold字段。

当您使用AttemptController Obj = new AttemptController(3, 2); 时，它将设置值。

使用时会设置MaxAttempts = 3和WarningAttempts = 2

AttemptController Obj = new AttemptController(3, 2);

当你使用时会设置MaxAttempts = 7和WarningAttempts = 5

AttemptController Obj1 = new AttemptController(7, 5);

static 字段让所有实例使用相同的字段值。

【讨论】：