/Gradebook.Data/Repositories/ClassSubjectRepository.cs

using Gradebook.Contracts.Repositories;

using Gradebook.Model;

using System;

using System.Collections.Generic;

using System.Data.Entity;

using System.Linq;



namespace Gradebook.Data.Repositories

{

    public class ClassSubjectRepository : Repository<ClassCode>, IClassSubjectRepository

    {

        public ClassSubjectRepository(DbContext dbContext) : base(dbContext) { }



        public IEnumerable<ClassCode> GetByTeacher(int teacherId)

        {

            if (!DbContext.Set<Teacher>().Any(x => x.Id == teacherId))

                throw new ArgumentException("teacherId");



            return DbSet.Include(x => x.Subject).Where(x => x.TeacherClassCodes.Any(y => y.TeacherId == teacherId));

        }

    }

}