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;
}
当我想编辑订单时，我将所选行传递到新窗口，如下所示：
OrderEditWindow orderEdit = new OrderEditWindow();
orderEdit.SelectedOrder = SelectedOrder;
orderEdit.ShowDialog();
这里我将Window的DataContext设置为：
DataContext = SelectedOrder;
在这个窗口中，我有另一个绑定到OrderDetails Order集合属性的数据网格。问题出在OrderDetails上的CRUD操作上。例如，在我添加一个新的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();
}
然后我从存储库中调用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();
}
}
我收到有关OrderId的错误消息。如果我设置了manualy导航属性和id我没有收到错误，但更改不会保存到db。
我的Order模型看起来像这样：
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));
}
}
}
我真的想尝试使用某种工作单元而且我不明白我应该如何在带有子集合的对象上应用CRUD并在同一时间更新UI （通过在ObservableCollection中工作并使用Binding ClientPhone, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged我的父窗口会在我输入时更新）
最终解决方案：
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();
}
答案 0 :(得分：2)
您可以通过这种方式添加和更新子项，但不确定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中对已删除的OrderDetail进行某种标记。
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();
}