📌تمرین جلسه 109 - امکان فیلتر روی ستون نام و نام خانوادگی

        void BindGridList(string search = "")
        {
            using (Toplearn_DB_Context context = new Toplearn_DB_Context())
            {
                var query = context.Courses
                    // .Where(c=> c.Title.Contains(search))
                    //  .OrderByDescending(c => c.CourseId)
                    .Select(c => new
                    {
                        c.CourseId,
                        c.Title,
                        c.Hours,
                        c.StudentCount,
                        TeacherName = context.Persons.Where(s => s.PersonId == c.TeacherId)
                        .Select(a => a.Name + " " + a.Family).Single(),
                        RegisterCount = context.StudentInCourses.Count(w => w.CourseId == c.CourseId)
                    })
                    .ToList();

                if (!string.IsNullOrWhiteSpace(search))
                {
                    query = query.Where(c => c.Title.Contains(search) || c.TeacherName.Contains(search)).ToList();
                }
                var result = query.OrderByDescending(c => c.CourseId).ToList();


                dgvPersons.AutoGenerateColumns = false;
                dgvPersons.DataSource = query;
            }
        }