C# 实体框架6.1：子对象上的CRUD

我使用来自存储库的对象列表填充数据网格，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;
    }

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

  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();

    }

 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));
        }
    }
}

在这里，我将窗口的DataContext设置为：

DataContext = SelectedOrder;

在这个窗口中，我有另一个数据网格，它绑定到

Order

的

OrderDetails

集合属性。问题在于

OrderDetails

上的CRUD操作。例如，在添加新的orderDetail后，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;
    }

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

  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();

    }

 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));
        }
    }
}

然后我从存储库调用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();
        }
    }

我得到一个关于OrderId的错误。如果我手动设置导航属性和id，我不会得到错误，但更改不会保存到数据库中

我的

订单

型号如下：

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

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

  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();

    }

 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));
        }
    }
}

我真的在尝试使用某种工作单元，但我不明白我应该如何在具有子集合的对象上应用CRUD，同时保持UI的更新（通过在

ObservableCollection

中工作并使用

绑定ClientPhone，Mode=TwoWay，UpdateSourceTrigger=PropertyChanged

我的父窗口在我键入时更新）

最终工作解决方案：

   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();
        }

使用（RSDContext context=new RSDContext（））
{
var details=order.OrderDetails；
order.OrderDetails=null；
列出原始或详细信息=
其中（o=>o.OrderId==order.OrderId）.Select（o=>o.OrderDetailId.ToList（）；
List CurrentOrderDetailsIds=details.Select（o=>o.OrderDetailId.ToList（）；
List DeletedOrderDetailsIds=originalordertailsids.Except（CurrentOrderDetailsIds.ToList（）；
context.Entry（order）.State=EntityState.Modified；
foreach（DeletedOrderDetailsIds中的变量deletedOrderDetailId）
{
context.Entry（context.OrderDetails.Single（o=>o.OrderDetailId==deletedOrderDetailId））.State=EntityState.Deleted；
}
foreach（详细的订单详细信息）
{
//加上。
if（detail.OrderDetailId==0）
{
detail.OrderId=order.OrderId；
context.Entry（detail.State=EntityState.Added；
}
//更新。
其他的
{
context.Entry（detail.State=EntityState.Modified；
}
}
SaveChanges（）；
}

您可以通过这种方式添加和更新子项，但不能确定ui中已删除的订单详细信息。如果您不想从实体获取订单，则需要在OrderDetail中为已删除的OrderDetail做某种标记

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();
}

---

我认为问题不在wpf中，但在EF中，您需要从包含详细信息的上下文中获取订单，然后将订单ui与订单数据库合并。如果我这样做，它会工作，但我会松开实时更新的ui。我知道我可以实现发布/订阅模式（我必须先学习）但是我希望有一个解决方案，因为我觉得拿一个对象，修改它的所有方面，然后把它推回db是很自然的。我认为

把它推回db

，因为子集合不仅仅是通过改变父对象的状态来完成的，你需要从ui和dbI合并子集合，我将研究如何做到这一点那。谢谢。*可能会循环遍历所有子对象并手动插入/删除它们。我会在保存方法中尝试。我想如果我在集合更改事件中这样做，我会打破我的工作单位心态。是的，这很有效。谢谢。我想这是最好的方法。我会研究如何知道我认为我需要的实体被删除要管理我自己，请删除删除代码，因为现在我使用Delete命令，当我处于此循环中时，我看不到已删除的对象。谢谢。*我想我可以与db中的对象进行比较并删除它们。@andySF，您可以添加名为

IsDeleted

的新属性并添加

[NotMapped]

属性，然后在删除项目时从UI中将其标记为true（通过订阅集合更改事件或删除按钮单击事件？）我在集合更改事件上设置了IsDeleted=true，但后来我意识到这是无用的，因为在foreach循环中，我无法迭代删除的项目，因为它们不在那里。在这种情况下，这是有意义的，我认为UI中的更改将通过某种

保存
b应用然后将删除的项目存储在其他集合中（+将其标记为已删除），并在发送到后端之前重新添加到集合中