当从数据库中删除模型数据时，除了主键被删除之外，我怎样才能删除所有这些数据？

Question

我正在开发一个列表框系统，操作员可以在其中选择用户机制中的练习并删除它们。目前，当调用RemoveExercises 时，它会删除与RegimeItem 相关联的所有数据，但与RegimeItemID 相关联的数据除外。 对于 RemoveExercises 函数，我已经开始使用 Session 以便 RequestedExercises 列表框随着所做的更改（添加和删除练习）进行更新。对于为什么不删除整个模型项目的任何帮助或建议，我们将不胜感激。如下所示，表格数据显示了“已删除”的项目，但项目 ID 仍然存在。

控制器（cs）

    [HttpGet]
    public ActionResult ExerciseIndex(int id, UserExerciseViewModel vmodel)
    {
        User user = db.Users.Find(id);
        UserExerciseViewModel model = new UserExerciseViewModel { AvailableExercises = GetAllExercises(), RequestedExercises = ChosenExercises(user, vmodel) };
        model.UserID = user.UserID;
        Session["UserExerciseViewModel"] = model;
        return View(model);
    }

    [HttpPost]
    public ActionResult ExerciseIndex(UserExerciseViewModel model, string add, string remove, string send, int id, RegimeItem item)//, User rUser) //int userID
    //public ActionResult ExerciseIndex(UserExerciseViewModel model, string add, string remove, string send, int id, RegimeItem item)
    {

        UserExerciseViewModel model2 = (UserExerciseViewModel)(Session["UserExerciseViewModel"]);
        model.RequestedExercises = model2.RequestedExercises;
        model.AvailableExercises = model2.AvailableExercises;
        if (!string.IsNullOrEmpty(add))
            AddExercises(model, id);
        else if (!string.IsNullOrEmpty(remove))
            RemoveExercises(model, id);
        return RedirectToAction("ExerciseIndex", new { id = model2.UserID, vmodel = model2 });
    }

    void RemoveExercises(UserExerciseViewModel model, int id)
    {
        var userExerciseViewModel = (UserExerciseViewModel)(Session["UserExerciseViewModel"]);
        foreach (int selected in model.RequestedSelected)
        {
            if (model.RequestedSelected != null)
            {
                User user = db.Users.Find(id);
                RegimeItem item = db.RegimeItems.Find(selected); // ---deletes the user associated with regimeitem
                item.RegimeExercise = this.GetAllExercises().FirstOrDefault(i => i.ExerciseID == selected); //--this removes the regimeexercise
                user.RegimeItems.Remove(item);
            }
        }
        db.SaveChanges();
    }

    private List<Exercise> GetAllExercises()
    {
        return db.Exercises.ToList();
    }

    private List<RegimeItem> ChosenExercises(User user, UserExerciseViewModel model)
    {
        return db.Users
     .Where(u => u.UserID == user.UserID)
     .SelectMany(u => u.RegimeItems)
     .ToList();
    }

模型（cs）

 public class User
    {
        public int UserID { get; set; }
        public ICollection<RegimeItem> RegimeItems { get; set; }
        public User()
        {
            this.RegimeItems = new List<RegimeItem>();
        } 
    }
    public class RegimeItem
    {
        public int RegimeItemID { get; set; }
        public Exercise RegimeExercise { get; set; }
    }

ViewModel(cs)

public class UserExerciseViewModel
{
    public List<Exercise> AvailableExercises { get; set; }
    public List<RegimeItem> RequestedExercises { get; set; }
    public int? SelectedExercise { get; set; }
    public int[] AvailableSelected { get; set; }
    public int[] RequestedSelected { get; set; }
    public string SavedRequested { get; set; }
    public int UserID { get; set; }
}

Answer 1

以下更改应该可以解决它：

void RemoveExercises(UserExerciseViewModel model, int id)
{
    var userExerciseViewModel = (UserExerciseViewModel)(Session["UserExerciseViewModel"]);
    foreach (int selected in model.RequestedSelected)
    {
        if (model.RequestedSelected != null)
        {
            User user = db.Users.Find(id);
            RegimeItem item = db.RegimeItems.Find(selected);
            item.RegimeExercise = this.GetAllExercises().FirstOrDefault(i => i.ExerciseID == selected); //--this removes the regimeexercise
            user.RegimeItems.Remove(item); //deletes the user's regimeitem
            db.RegimeItems.Remove(item); //removes the regimeitem itself 
        }
    }
    db.SaveChanges();
}