c#对象生命周期

[d1135130491]

在方法内实例对象，当方法调用结束后，gc就把对象的引用回收了，我输入的数据也找不到了，请问怎么才能让对象不被回收，在原有的代码基础上

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

namespace 实验4
{
    class Student//学生类
    {
        string name;
        string id;
        string english;
        string chinese;
        string math;

        public string Name
        {
            set { name = value; }
            get { return name; }
        }
        public string Id
        {
            set { id = value; }
            get { return id; }
        }
        public string English
        {
            set { english = value; }
            get { return english; }
        }
        public string Chinese
        {
            set { chinese = value; }
            get { return chinese; }
        }
        public string Math
        {
            set { math = value; }
            get { return math; }
        }
     
    }

    public class manager//管理类
    {
        static int num = 0;
        Student[] student = new Student[10];
        public void addStudent()//添加学生信息
        {
            student[num] = new Student();
            Console.Write("\t\t\t\t请输入姓名：");
            student[num].Name = Console.ReadLine();
            Console.Write("\t\t\t\t请输入学号：");
            student[num].Id = Console.ReadLine();
            Console.Write("\t\t\t\t请输入英语成绩：");
            student[num].English = Console.ReadLine();
            Console.Write("\t\t\t\t请输入语文成绩：");
            student[num].Chinese = Console.ReadLine();
            Console.Write("\t\t\t\t请输入数学成绩：");
            student[num].Math = Console.ReadLine();
            Console.WriteLine("\t\t\t\t**添加成功！**");
        }

        public void alterStudent()
        {
            string xh;
            string item;
            Console.WriteLine("修改成绩，需要输入学号：");
            xh = Console.ReadLine();
            for (int i = 0; i <= num; i++)
            {
                if (student[num].Id == xh)
                {
                    Console.WriteLine("请输入要修改的项目:");
                    item = Console.ReadLine();
                    if (item == "英语")
                    {
                        Console.WriteLine("请输入新成绩：");
                        student[num].English = Console.ReadLine();
                    }
                    else if (item == "语文")
                    {
                        Console.WriteLine("请输入新成绩：");
                        student[num].Chinese = Console.ReadLine();
                    }
                    else if (item == "数学")
                    {
                        Console.WriteLine("请输入新成绩：");
                        student[num].Math = Console.ReadLine();
                    }
                }
            }
        }
    }
}

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

namespace 实验4
{
    class Program
    {
        static void Main(string[] args)
        {
            int functionSelect;
            while (true)
            {
                Console.WriteLine("\t\t\t*********************************");
                Console.WriteLine("\t\t\t*\t学生信息管理系统\t*");
                Console.WriteLine("\t\t\t*\t\t\t\t*"); ;
                Console.WriteLine("\t\t\t*\t\t\t\t*");
                Console.WriteLine("\t\t\t*  1.添加 2.修改 3.删除 4.查询  *");
                Console.WriteLine("\t\t\t*********************************");
                functionSelect = Convert.ToInt32(Console.ReadLine());
                manager m = new manager();
                switch (functionSelect)
                { 
                    case 1:
                        m.addStudent();
                        break;
                    case 2:
                        m.alterStudent();
                        break;
                    case 3:
                        break;
                    case 4:
                        break;
                }
            }
        }
    }
}

[threenewbee]

manager m = new manager(); 没有必要每次初始化一次 放在 Main函数的开头

[d1135130491]

跪了，我一个星期没解决的问题，你一句话就解决了。