實體框架6.1：對子對象的CRUD

Question

我用來自存儲庫的對象列表填充數據網格，如下所示：

   public static IEnumerable<Order> GetOrdersForDataGrid()
    {
        IEnumerable<Order> query;
        using (RSDContext = new RSDContext())
        {
            query = context.Orders.Include(o=>o.OrderDetails).ToList();
        }
        return query;
    }

當我要編輯訂單時，將選定的行傳遞到新窗口，如下所示：

 OrderEditWindow orderEdit = new OrderEditWindow();
        orderEdit.SelectedOrder = SelectedOrder;
        orderEdit.ShowDialog();

在這里，我將窗口的DataContext設置為：

DataContext = SelectedOrder;

在此窗口中，我還有另一個數據網格，該數據網格綁定到Order OrderDetails集合屬性。 問題在於在OrderDetails上的CRUD操作。 例如，在我像這樣添加新的orderDetail之后：

  private void AddProductDetailButton_OnClick(object sender, RoutedEventArgs e)
    {
        if (!ValidateProductDetail())
            return;
        var _selectedProduct = ProductAutoCompleteBox.SelectedItem as Product;
        var selectedProduct = ProductsRepository.GetProductById(_selectedProduct.ProductId);
        OrderDetail orderDetail = new OrderDetail();
        orderDetail.Price = selectedProduct.Price;
        orderDetail.ProductCode = selectedProduct.Code;
        orderDetail.ProductName = selectedProduct.Name;
        orderDetail.Quantity = int.Parse(QuantityNumericUpDown.Value.ToString());
        orderDetail.Um = selectedProduct.Um;
        orderDetail.Total = selectedProduct.Price * int.Parse(QuantityNumericUpDown.Value.ToString());
        orderDetail.Group = selectedProduct.Subgroup.Group.Name;
        orderDetail.Subgroup = selectedProduct.Subgroup.Name;
        orderDetail.SupplierName = selectedProduct.Supplier.Name;
        //orderDetail.Order=SelectedOrder;
        //orderDetail.OrderId = SelectedOrder.OrderId;
        SelectedOrder.OrderDetails.Add(orderDetail);

        ProductAutoCompleteBox.Text = string.Empty;
        QuantityNumericUpDown.Value = 1;
        ProductAutoCompleteBox.Focus();

    }

然后從存儲庫調用update方法：

  public static void UpdateOrder(Order order)
    {
        using (RSDContext context = new RSDContext())
        {
            context.Orders.Attach(order);
            context.Entry(order).State = EntityState.Modified;
            context.SaveChanges();
        }
    }

我收到有關OrderId的錯誤。 如果我手動設置導航屬性和ID，我不會收到錯誤，但是更改不會保存到數據庫中。

我的Order模型如下所示：

 public  class Order : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public Order()
    {
        _OrderDetails = new ObservableCollection<OrderDetail>();
        _OrderDetails.CollectionChanged += _OrderDetails_CollectionChanged;
    }

    void _OrderDetails_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        if (e.NewItems != null)
            AttachProductChangedEventHandler(e.NewItems.Cast<OrderDetail>());
        if (e.OldItems != null)
            CalcualteTotals();
    }
    [NotMapped]
    public decimal CalculatedTotal
    {
        get
        {
            return OrderDetails.Sum(x => x.Total);
        }
    }
    public int OrderId { get; set; }

    private int _Number;

    public int Number
    {
        get { return _Number; }
        set
        {
            _Number = value;
            NotifyPropertyChanged("Number");
        }
    }

    private DateTime _Date;

    public DateTime Date
    {
        get { return _Date; }
        set
        {
            _Date = value;
            NotifyPropertyChanged("Date");
        }
    }

    private bool _Canceled;

    public bool Canceled
    {
        get { return _Canceled; }
        set
        {
            _Canceled = value;
            NotifyPropertyChanged("Canceled");
        }
    }
    private string _ClientName;

    public string ClientName
    {
        get { return _ClientName; }
        set
        {
            _ClientName = value;
            NotifyPropertyChanged("ClientName");
        }
    }
    private string _ClientPhone;

    public string ClientPhone
    {
        get { return _ClientPhone; }
        set
        {
            _ClientPhone = value;
            NotifyPropertyChanged("ClientPhone");
        }
    }

    private string _DeliveryAddress;

    public string DeliveryAddress
    {
        get { return _DeliveryAddress; }
        set
        {
            _DeliveryAddress = value;
            NotifyPropertyChanged("DeliveryAddress");
        }
    }

    private decimal _Transport;

    public decimal Transport
    {
        get { return _Transport; }
        set
        {
            _Transport = value;
            NotifyPropertyChanged("Transport");
        }
    }

    private decimal _Total;

    public decimal Total
    {
        get { return _Total; }
        set
        {
            _Total = value;
            NotifyPropertyChanged("Total");
        }
    }



    private ObservableCollection<OrderDetail> _OrderDetails;

    public virtual ObservableCollection<OrderDetail> OrderDetails
    {
        //get { return _OrderDetails ?? (_OrderDetails = new ObservableCollection<OrderDetail>()); }
        get
        {
            return _OrderDetails;
        }
        set
        {
            _OrderDetails = value;
            NotifyPropertyChanged("OrderDetails");
        }
    }
    private void AttachProductChangedEventHandler(IEnumerable<OrderDetail> orderDetails)
    {

        foreach (var p in orderDetails)
        {
            p.PropertyChanged += (sender, e) =>
            {
                switch (e.PropertyName)
                {
                    case "Quantity":
                    case "Price":
                    case "Total":
                        CalcualteTotals();
                        break;
                }
            };
        }

        CalcualteTotals();
    }

    public void CalcualteTotals()
    {
        NotifyPropertyChanged("CalculatedTotal");

    }
    public void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this,
                new PropertyChangedEventArgs(propertyName));
        }
    }
}

我的OrderDetail模型如下所示：

 public class OrderDetail : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;


    public int OrderDetailId { get; set; }
    public int OrderId { get; set; }

    public Order Order { get; set; }

    private int _ProductCode;
    public int ProductCode
    {
        get { return _ProductCode; }
        set
        {
            _ProductCode = value;
            NotifyPropertyChanged("ProductCode");
        }
    }

    private string _ProductName;

    public string ProductName
    {
        get { return _ProductName; }
        set
        {
            _ProductName = value;
            NotifyPropertyChanged("ProductName");
        }
    }

    private string _Um;

    public string Um
    {
        get { return _Um; }
        set
        {
            _Um = value;
            NotifyPropertyChanged("Um");
        }
    }

    private decimal _Price;

    public decimal Price
    {
        get { return _Price; }
        set
        {
            _Price = value;
            NotifyPropertyChanged("Price");
            NotifyPropertyChanged("Total");

        }
    }

    private int _Quantity;

    public int Quantity
    {
        get { return _Quantity; }
        set
        {
            _Quantity = value;
            NotifyPropertyChanged("Quantity");
            NotifyPropertyChanged("Total");

        }
    }

    private string _SupplierName;

    public string SupplierName
    {
        get { return _SupplierName; }
        set
        {
            _SupplierName = value;
            NotifyPropertyChanged("SupplierName");
        }
    }

    private string _Subgroup;

    public string Subgroup
    {
        get { return _Subgroup; }
        set
        {
            _Subgroup = value;
            NotifyPropertyChanged("Subgroup");
        }
    }

    private string _Group;

    public string Group
    {
        get { return _Group; }
        set
        {
            _Group = value;
            NotifyPropertyChanged("Group");
        }
    }

    public decimal _Total;

    public decimal Total
    {
        get { return Quantity * Price; }
        set
        {
            _Total = value;
            NotifyPropertyChanged("Total");
        }
    }

    public void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this,
                new PropertyChangedEventArgs(propertyName));
        }
    }
}

我真的在嘗試使用某種工作單元，但我不明白如何將CRUD應用到具有子集合的對象上並同時更新UI（通過在ObservableCollection工作並使用Binding ClientPhone, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged我的父窗口在輸入時會更新）

最終的工作解決方案：

   using (RSDContext context = new RSDContext())
        {
            var details = order.OrderDetails;
            order.OrderDetails = null;
            List<int> OriginalOrderDetailsIds =
             context.OrderDetails.Where(o => o.OrderId == order.OrderId).Select(o => o.OrderDetailId).ToList();
            List<int> CurrentOrderDetailsIds = details.Select(o => o.OrderDetailId).ToList();
            List<int> DeletedOrderDetailsIds = OriginalOrderDetailsIds.Except(CurrentOrderDetailsIds).ToList();

            context.Entry(order).State = EntityState.Modified;
            foreach (var deletedOrderDetailId in DeletedOrderDetailsIds)
            {
                context.Entry(context.OrderDetails.Single(o => o.OrderDetailId == deletedOrderDetailId)).State = EntityState.Deleted;
            }
            foreach (OrderDetail detail in details)
            {
                // Add.
                if (detail.OrderDetailId == 0)
                {
                    detail.OrderId = order.OrderId;
                    context.Entry(detail).State = EntityState.Added;
                }
                // Update.
                else
                {
                    context.Entry(detail).State = EntityState.Modified;
                }
            }
            context.SaveChanges();
        }

Answer 1

您可以通過這種方式添加和更新子項，但是不確定ui中已刪除的訂單詳細信息。 如果您不想從實體獲取訂單，則需要在OrderDetail中對已刪除的OrderDetail進行某種標記。

using (RSDContext context = new RSDContext())
{
    var details = order.OrderDetails;
    order.OrderDetails = null;

    context.Entry(order).State = EntityState.Modified;
    foreach (var detail in details)
    {
        if (detail.Id == 0)
        {
            // Adds.
            detail.OrderId = order.Id;
            context.Entry(detail).State = EntityState.Added;
        }
        else if (detail.IsDeleted)
        // Adds new property called 'IsDeleted' 
        //  and add [NotMapped] attribute 
        //  then mark this property as true from the UI for deleted items.
        {
           // Deletes.
           context.Entry(detail).State = EntityState.Deleted;
        }
        else
        {
           // Updates.
           context.Entry(detail).State = EntityState.Modified;
        }
    }

    order.OrderDetails = details;
    context.SaveChanges();
}