EF_Code_First/EF_Code_First/Models/Grade.cs

using System;
using System.ComponentModel.DataAnnotations.Schema;
using System.Text;

namespace EF_Code_First.Models
{
    public class Grade
    {
        public int GradeId { get; set; }
        public string? GradeName { get; set; }
        public string? Section { get; set; }
        [ForeignKey("StudentId")]
        public ICollection<Student>? Students { get; set; }


        public override string ToString()
        {
            StringBuilder builder = new StringBuilder();
            builder.Append(GradeId);
            builder.Append('\u002C');
            builder.Append(GradeName);
            builder.Append('\u002C');
            builder.Append(Students.Count);
            return builder.ToString();
        }
    }
}