EntityChangedParams クラス
定義
重要
一部の情報は、リリース前に大きく変更される可能性があるプレリリースされた製品に関するものです。 Microsoft は、ここに記載されている情報について、明示または黙示を問わず、一切保証しません。
PropertyChanged デリゲートの引数をカプセル化します。
public ref class EntityChangedParams sealedpublic sealed class EntityChangedParamstype EntityChangedParams = classPublic NotInheritable Class EntityChangedParams- 継承
-
EntityChangedParams
例
XAML ファイルの次の分離コード ページでは、バインディング コレクションにバインドされているデータに変更が発生したときに呼び出されるカスタム メソッドを含む DataServiceCollection<T> が作成されます。
CollectionChanged イベントが発生すると、指定されたメソッドは、バインド コレクションから削除された項目がデータ サービスから削除されないようにします。
PropertyChanged イベントが発生すると、ShipDate値が検証され、出荷済みの注文に変更が加えられないことが確認されます。
using System;
using System.Collections.Specialized;
using System.Data.Services.Client;
using System.Linq;
using System.Windows;
using NorthwindClient.Northwind;
namespace NorthwindClient
{
public partial class CustomerOrdersCustom : Window
{
private NorthwindEntities context;
private DataServiceCollection<Customer> trackedCustomers;
private const string customerCountry = "Germany";
private const string svcUri = "http://localhost:12345/Northwind.svc/";
public CustomerOrdersCustom()
{
//InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
try
{
// Initialize the context for the data service.
context = new NorthwindEntities(new Uri(svcUri));
// Create a LINQ query that returns customers with related orders.
var customerQuery = from cust in context.Customers.Expand("Orders")
where cust.Country == customerCountry
select cust;
// Create a new collection for binding based on the LINQ query.
trackedCustomers = new DataServiceCollection<Customer>(customerQuery,
TrackingMode.AutoChangeTracking,"Customers",
OnPropertyChanged, OnCollectionChanged);
// Bind the root StackPanel element to the collection;
// related object binding paths are defined in the XAML.
LayoutRoot.DataContext = trackedCustomers;
}
catch (DataServiceQueryException ex)
{
MessageBox.Show("The query could not be completed:\n" + ex.ToString());
}
catch (InvalidOperationException ex)
{
MessageBox.Show("The following error occurred:\n" + ex.ToString());
}
}
// Method that is called when the CollectionChanged event is handled.
private bool OnCollectionChanged(
EntityCollectionChangedParams entityCollectionChangedinfo)
{
if (entityCollectionChangedinfo.Action ==
NotifyCollectionChangedAction.Remove)
{
// Delete the related items when an order is deleted.
if (entityCollectionChangedinfo.TargetEntity.GetType() == typeof(Order))
{
// Get the context and object from the supplied parameter.
DataServiceContext context = entityCollectionChangedinfo.Context;
Order deletedOrder = entityCollectionChangedinfo.TargetEntity as Order;
if (deletedOrder.Order_Details.Count == 0)
{
// Load the related OrderDetails.
context.LoadProperty(deletedOrder, "Order_Details");
}
// Delete the order and its related items;
foreach (Order_Detail item in deletedOrder.Order_Details)
{
context.DeleteObject(item);
}
// Delete the order and then return true since the object is already deleted.
context.DeleteObject(deletedOrder);
return true;
}
else
{
return false;
}
}
else
{
// Use the default behavior.
return false;
}
}
// Method that is called when the PropertyChanged event is handled.
private bool OnPropertyChanged(EntityChangedParams entityChangedInfo)
{
// Validate a changed order to ensure that changes are not made
// after the order ships.
if ((entityChangedInfo.Entity.GetType() == typeof(Order)) &&
((Order)(entityChangedInfo.Entity)).ShippedDate < DateTime.Today)
{
throw new ApplicationException(string.Format(
"The order {0} cannot be changed because it shipped on {1}.",
((Order)(entityChangedInfo.Entity)).OrderID,
((Order)(entityChangedInfo.Entity)).ShippedDate));
}
return false;
}
private void deleteButton_Click(object sender, RoutedEventArgs e)
{
if (customerIDComboBox.SelectedItem != null)
{
// Get the Orders binding collection.
DataServiceCollection<Order> trackedOrders =
((Customer)(customerIDComboBox.SelectedItem)).Orders;
// Remove the currently selected order.
trackedOrders.Remove((Order)(ordersDataGrid.SelectedItem));
}
}
private void saveChangesButton_Click(object sender, RoutedEventArgs e)
{
try
{
// Save changes to the data service.
context.SaveChanges();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
}
}
Imports System.Collections.Specialized
Imports System.Data.Services.Client
Imports System.Windows
Imports northwindclientvb.Northwind
Partial Public Class CustomerOrdersCustom
Inherits Window
Private context As NorthwindEntities
'Private trackedCustomers As DataServiceCollection(Of Customer)
'Private Sub Window_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
' Try
' ' Initialize the context for the data service.
' context = New NorthwindEntities(New Uri(SvcUri))
' '<snippetMasterDetailBinding>
' ' Create a LINQ query that returns customers with related orders.
' Dim customerQuery = From cust In context.Customers.Expand("Orders")
' Where cust.Country = CustomerCountry
' Select cust
' ' Create a new collection for binding based on the LINQ query.
' trackedCustomers = New DataServiceCollection(Of Customer)(customerQuery,
' TrackingMode.AutoChangeTracking, "Customers",
' AddressOf OnMyPropertyChanged, AddressOf OnMyCollectionChanged)
' ' Bind the root StackPanel element to the collection
' ' related object binding paths are defined in the XAML.
' Me.LayoutRoot.DataContext = trackedCustomers
' '</snippetMasterDetailBinding>
' Catch ex As DataServiceQueryException
' MessageBox.Show("The query could not be completed:\n" + ex.ToString())
' Catch ex As InvalidOperationException
' MessageBox.Show("The following error occurred:\n" + ex.ToString())
' End Try
'End Sub
' Method that is called when the CollectionChanged event is handled.
'Private Function OnMyCollectionChanged( _
' ByVal entityCollectionChangedinfo As EntityCollectionChangedParams) As Boolean
' If entityCollectionChangedinfo.Action = _
' NotifyCollectionChangedAction.Remove Then
' ' Delete the related items when an order is deleted.
' If entityCollectionChangedinfo.TargetEntity.GetType() Is GetType(Order) Then
' ' Get the context and object from the supplied parameter.
' Dim context = entityCollectionChangedinfo.Context
' Dim deletedOrder As Order = _
' CType(entityCollectionChangedinfo.TargetEntity, Order)
' If deletedOrder.Order_Details.Count = 0 Then
' ' Load the related OrderDetails.
' context.LoadProperty(deletedOrder, "Order_Details")
' End If
' ' Delete the order and its related items
' For Each item As Order_Detail In deletedOrder.Order_Details
' context.DeleteObject(item)
' Next
' ' Delete the order and then return false since the object is already deleted.
' context.DeleteObject(deletedOrder)
' Return True
' Else
' Return False
' End If
' Else
' ' Use the default behavior.
' Return False
' End If
'End Function
'' Method that is called when the PropertyChanged event is handled.
'Private Function OnMyPropertyChanged(
'ByVal entityChangedInfo As EntityChangedParams) As Boolean
' ' Validate a changed order to ensure that changes are not made
' ' after the order ships.
' If entityChangedInfo.Entity.GetType() Is GetType(Order) AndAlso
' (CType(entityChangedInfo.Entity, Order).ShippedDate < DateTime.Today) Then
' Throw New ApplicationException(String.Format(
' "The order {0} cannot be changed because it shipped on {1}.",
' CType(entityChangedInfo.Entity, Order).OrderID,
' CType(entityChangedInfo.Entity, Order).ShippedDate))
' Return False
' Else
' Return True
' End If
'End Function
'Private Sub deleteButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
' ' Get the Orders binding collection.
' If customerIDComboBox.SelectedItem IsNot Nothing Then
' Dim trackedOrders As DataServiceCollection(Of Order) = _
' (CType(customerIDComboBox.SelectedItem, Customer)).Orders
' ' Remove the currently selected order.
' trackedOrders.Remove(CType(ordersDataGrid.SelectedItem, Order))
' End If
'End Sub
'Private Sub saveChangesButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
' Try
' ' Save changes to the data service.
' context.SaveChanges()
' Catch ex As Exception
' MessageBox.Show(ex.ToString())
' End Try
'End Sub
End Class
Imports System.Collections.Specialized
Imports System.Data.Services.Client
Imports System.Linq
Imports System.Windows
Imports northwindclientvb.Northwind
Imports northwindclientvb.NorthwindModel
Partial Public Class CustomerOrdersCustom
Inherits Window
Private _context As Northwind.NorthwindEntities
Private _trackedCustomers As DataServiceCollection(Of Customer)
Private Const CustomerCountry As String = "Germany"
Private Const SvcUri As String = "http://localhost:12345/Northwind.svc/"
Private Sub Window_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
Try
' Initialize the context for the data service.
context = New Northwind.NorthwindEntities(New Uri(SvcUri))
' Create a LINQ query that returns customers with related orders.
Dim customerQuery = From cust In context.Customers.Expand("Orders")
Where cust.Country = CustomerCountry
Select cust
' Create a new collection for binding based on the LINQ query.
_trackedCustomers = New DataServiceCollection(Of Customer)(customerQuery,
TrackingMode.AutoChangeTracking, "Customers",
AddressOf OnMyPropertyChanged, AddressOf OnMyCollectionChanged)
' Bind the root StackPanel element to the collection
' related object binding paths are defined in the XAML.
Me.LayoutRoot.DataContext = _trackedCustomers
Me.LayoutRoot.UpdateLayout()
Catch ex As DataServiceQueryException
MessageBox.Show("The query could not be completed:\n" + ex.ToString())
Catch ex As InvalidOperationException
MessageBox.Show("The following error occurred:\n" + ex.ToString())
End Try
End Sub
' Method that is called when the CollectionChanged event is handled.
Private Function OnMyCollectionChanged( _
ByVal entityCollectionChangedinfo As EntityCollectionChangedParams) As Boolean
If entityCollectionChangedinfo.Action = _
NotifyCollectionChangedAction.Remove Then
' Delete the related items when an order is deleted.
If entityCollectionChangedinfo.TargetEntity.GetType() Is GetType(Orders) Then
' Get the context and object from the supplied parameter.
Dim context = entityCollectionChangedinfo.Context
Dim deletedOrder As Orders = _
CType(entityCollectionChangedinfo.TargetEntity, Orders)
' Load the related OrderDetails.
context.LoadProperty(deletedOrder, "Order_Details")
' Delete the order and its related items
For Each item As Order_Details In deletedOrder.Order_Details
'context.DeleteLink(deletedOrder, "Order_Details", item)
context.DeleteObject(item)
Next
' Delete the order and then return false since the object is already deleted.
context.DeleteObject(deletedOrder)
Return False
Else
Return True
End If
Else
' Use the default behavior.
Return True
End If
End Function
' Method that is called when the PropertyChanged event is handled.
Private Function OnMyPropertyChanged(
ByVal entityChangedInfo As EntityChangedParams) As Boolean
' Validate a changed order to ensure that changes are not made
' after the order ships.
If entityChangedInfo.Entity.GetType() Is GetType(Orders) AndAlso
(CType(entityChangedInfo.Entity, Orders).ShippedDate < DateTime.Today) Then
Throw New ApplicationException(String.Format(
"The order {0} cannot be changed because it shipped on {1}.",
CType(entityChangedInfo.Entity, Orders).OrderID,
CType(entityChangedInfo.Entity, Orders).ShippedDate))
End If
Return True
End Function
Private Sub deleteButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
' Get the Orders binding collection.
Dim trackedOrders As DataServiceCollection(Of Orders) = _
(CType(customerIDComboBox.SelectedItem, Customers)).Orders
' Remove the currently selected order.
trackedOrders.Remove(CType(ordersDataGrid.SelectedItem, Orders))
End Sub
Private Sub saveChangesButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
Try
' Save changes to the data service.
context.SaveChanges()
Catch ex As Exception
MessageBox.Show(ex.ToString())
End Try
End Sub
End Class
次の XAML コードは、前の例のウィンドウを定義します。
<Window x:Class="CustomerOrdersCustom"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Height="423" Width="679" Loaded="Window_Loaded" >
<StackPanel Orientation="Vertical" Height="Auto" Name="LayoutRoot" Width="Auto">
<Label Content="Customer ID" Margin="20,0,0,0" />
<ComboBox Name="customerIDComboBox" DisplayMemberPath="CustomerID" ItemsSource="{Binding}"
IsSynchronizedWithCurrentItem="True" SelectedIndex="0" Height="23" Width="120"
HorizontalAlignment="Left" Margin="20,0,0,0" VerticalAlignment="Center" />
<ListView ItemsSource="{Binding Path=Orders}" Name="ordersDataGrid" Margin="34,46,34,50">
<ListView.View>
<GridView AllowsColumnReorder="False" ColumnHeaderToolTip="Line Items">
<GridViewColumn DisplayMemberBinding="{Binding Path=OrderID, Mode=OneWay}"
Header="Order ID" Width="50"/>
<GridViewColumn DisplayMemberBinding="{Binding Path=OrderDate, Mode=TwoWay}"
Header="Order Date" Width="50"/>
<GridViewColumn DisplayMemberBinding="{Binding Path=Freight, Mode=TwoWay}"
Header="Freight Cost" Width="50"/>
</GridView>
</ListView.View>
</ListView>
<StackPanel Orientation="Horizontal">
<Button Name="deleteButton" Content="Delete Order" Click="deleteButton_Click"
Width="80" Height="30" Margin="450,0,10,0"/>
<Button Name="saveChangesButton" Content="Save Changes" Click="saveChangesButton_Click"
Width="80" Height="30" Margin="10,0,0,0"/>
</StackPanel>
</StackPanel>
</Window>
プロパティ
| 名前 | 説明 |
|---|---|
| Context |
変更されたエンティティ オブジェクトに関連付けられているコンテキスト。 |
| Entity |
変更されたエンティティ オブジェクト。 |
| PropertyName |
ターゲット オブジェクトを参照するエンティティ オブジェクトのプロパティの名前。 |
| PropertyValue |
エンティティ オブジェクトの変更されたプロパティによって現在参照されているオブジェクト。 |
| SourceEntitySet |
ソース オブジェクトのエンティティ セット。 |
| TargetEntitySet |
ターゲット エンティティ オブジェクトが属するエンティティ セット。 |
メソッド
| 名前 | 説明 |
|---|---|
| Equals(Object) |
指定したオブジェクトが現在のオブジェクトと等しいかどうかを判断します。 (継承元 Object) |
| GetHashCode() |
既定のハッシュ関数として機能します。 (継承元 Object) |
| GetType() |
現在のインスタンスの Type を取得します。 (継承元 Object) |
| MemberwiseClone() |
現在の Objectの簡易コピーを作成します。 (継承元 Object) |
| ToString() |
現在のオブジェクトを表す文字列を返します。 (継承元 Object) |