public void Delete(Lesson lesson)
 {
     using (var db = new EducationCourses())
     {
         db.Lessons.Attach(lesson);
         db.Lessons.Remove(lesson);
         db.SaveChanges();
         if (this.LessonDeleted != null)
             this.LessonDeleted(this, new CustomEventArgs<Lesson>(lesson));
     }
 }
 public void Insert(string name)
 {
     using (var db=new EducationCourses())
     {
         Lesson lesson = new Lesson { ID = Guid.NewGuid(), Name = name };
         db.Lessons.Add(lesson);
         db.SaveChanges();
         if (this.LessonAdded != null)
             this.LessonAdded(this, new CustomEventArgs<Lesson>(lesson));
     }
 }
        /// <summary>
        /// متد حذف
        /// </summary>
        /// <param name="lesson"></param>
        private void Delete(Lesson lesson)
        {
            try
            {

                this._repository.Delete(lesson);
            }
            catch
            {
            }
        }
 /// <summary>
 /// متد چک کردن برای حذف
 /// </summary>
 /// <returns></returns>
 private bool CanDelete(Lesson lesson)
 {
     return lesson != null;
 }