如何在Linq中编写带有案例的左连接(C# MVC)

using System;
using System.Collections.Generic;
using System.Linq;

public class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class Course
{
    public int StudentId { get; set; }
    public string CourseName { get; set; }
}

public class Program
{
    public static void Main()
    {
        var students = new List<Student>
        {
            new Student { Id = 1, Name = "Alice" },
            new Student { Id = 2, Name = "Bob" },
            new Student { Id = 3, Name = "Charlie" }
        };

        var courses = new List<Course>
        {
            new Course { StudentId = 1, CourseName = "Math" },
            new Course { StudentId = 2, CourseName = "Science" }
        };

        var result = from student in students
                     join course in courses on student.Id equals course.StudentId into studentCourses
                     from sc in studentCourses.DefaultIfEmpty()
                     select new
                     {
                         StudentName = student.Name,
                         CourseName = sc?.CourseName
                     };

        foreach (var item in result)
        {
            Console.WriteLine($"Student: {item.StudentName}, Course: {item.CourseName ?? "None"}");
        }
    }
}

Student: Alice, Course: Math
Student: Bob, Course: Science
Student: Charlie, Course: None