问如何使用iComparable compareTo方法对此数组进行排序？

EN

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

namespace StudentGradeOrder
{
    class Student : IComparable
    {

        private string firstName;
        private string lastName;
        private string degree;
        private int grade;

        /*Implementation of Parameterized constructor */
        public Student(string firstName, string lastName, string degree, int grade)
        {
            this.firstName = firstName;
            this.lastName = lastName;
            this.degree = degree;
            this.grade = grade;

        }

        /*Implementation of ToString method */
        public override string ToString()
        {
            return String.Format("{0} , {1}, {2} Grade {3}", lastName, firstName, degree, grade);
        }

        /*Implementation of CompareTo method */
        public int CompareTo(object obj)
        {

            Student studentObject = (Student)obj;

            var firstnameofStudent = studentObject.firstName.CompareTo(firstName);
            if (firstnameofStudent == 0)
            {
                var degreeValue = studentObject.degree.CompareTo(degree);
                if (degreeValue == 0)
                {
                    var gradeValue = studentObject.grade.CompareTo(grade);
                    if (gradeValue == 0)
                    {
                        var lastnameofStudent = studentObject.lastName.CompareTo(lastName);
                        if (lastnameofStudent == 0)

                            return lastnameofStudent;
                    }
                    return gradeValue;
                }
                return degreeValue;
            }
            return firstnameofStudent;
        }