c# - 无法从C#中的相同类但使用不同方法访问对象属性

Question

我无法在同一类的方法ClassOperations()中访问在Program类的Main()方法中创建的student1对象的属性。我不断

error CS0103: The name 'student1' does not exist in the current context

using System;

namespace Trials
{
    public class Students
    {
      public int maths;
      public int science;
      public int english;
      public int secondLang;
      public int socialScience;
      public string name;

      public Students(int[] inputMarks)
      {
        maths = inputMarks[0];
        science = inputMarks[1];
        english = inputMarks[2];
        secondLang = inputMarks[3];
        socialScience = inputMarks[4];
      }
    }

    public class Program
    {
      static void Main(string[] args)
        {
            Console.WriteLine("Enter your name: ");
            string inputName = Console.ReadLine();
            int[] marks = new int[5];

            Console.WriteLine("Enter the maths marks: ");
            marks[0] = int.Parse(Console.ReadLine());

            Console.WriteLine("Enter the Science marks: ");
            marks[1] = int.Parse(Console.ReadLine());

            Console.WriteLine("Enter the English marks: ");
            marks[2] = int.Parse(Console.ReadLine());

            Console.WriteLine("Enter the Second language marks: ");
            marks[3] = int.Parse(Console.ReadLine());

            Console.WriteLine("Enter the Social Science marks: ");
            marks[4] = int.Parse(Console.ReadLine());

            Students student1 = new Students(marks);

            student1.name = inputName;
            ClassOperations();
        }

      static void ClassOperations()
      {
          Console.WriteLine("Enter input :");
          int input = int.Parse(Console.ReadLine());

          switch (input)
          {
            case 1:
              Console.WriteLine(student1.name);
              break;
            case 2:
              Console.WriteLine(student1.maths);
              break;
            case 3:
              Console.WriteLine(student1.science);
              break;
            case 4:
              Console.WriteLine(student1.english);
              break;
            case 5:
              Console.WriteLine(student1.secondLang);
              break;
            case 6:
              Console.WriteLine(student1.socialScience);
              break;
        }
      }
    }
}

Answer 1

该错误告诉您问题所在:在方法(student1)中声明的局部变量(Main)在其他方法(ClassOperations，当前上下文)中无法访问。您有几种选择:

(静态)属性

(静态)字段

方法参数

在此示例中，“最佳”选项是将 student1变量作为参数传递给 ClassOperations方法:

static void Main(string[] args) {
    // setup elided
    Students student1 = new Students(marks);
    student1.name = inputName;  
    // pass as parameter    
    ClassOperations(student1);
} 

static void ClassOperations(Students student) {
    // access value via new name "student" 
    Console.WriteLine(student.name);
}

根据您的评论，这是带有字段的替代项的外观:

static Students student; //static field 
static void Main(string[] args) {
    // setup elided
    // initialize static field 
    student = new Students(marks);
    student.name = inputName;  
    ClassOperations();
} 

static void ClassOperations() {
    // access value via static field "student" 
    Console.WriteLine(student.name);
}