Gewusst wie: Zuordnen von benutzerdefinierten Objekten zu Entitäten (Entity Framework)
Wenn Sie benutzerdefinierte Datenklassen mit einem Entitätsdatenmodell (EDM) verwenden, müssen Sie die EDM-Attribute hinzufügen, mit denen benutzerdefinierte Klassen und Eigenschaften den im konzeptionellen Modell definierten Entitäten zugeordnet werden. Die Namen der Klassen und Eigenschaften müssen mit den Namen der Entitätstypen und Eigenschaften im konzeptionellen Modell übereinstimmen. Außerdem müssen die benutzerdefinierten Datenklassen für eine der folgenden Aufgaben aktualisiert werden:
Weitere Informationen finden Sie unter Objekt-Entität-Mappingattribute (Entity Framework).
So fügen Sie EDM-Attribute zu benutzerdefinierten Datenklassen hinzu
Fügen Sie der Codepage folgende using-Anweisungen (Imports in Visual Basic) hinzu:
Imports System.Data Imports System.Data.Objects.DataClasses Imports System.Data.Metadata.Edm Imports Microsoft.Samples.Edmusing System.Data; using System.Data.Objects.DataClasses; using System.Data.Metadata.Edm; using Microsoft.Samples.Edm;Fügen Sie EdmSchemaAttribute unmittelbar über der Namespacedeklaration ein.
Fügen Sie eine Instanz von EdmRelationshipAttribute für jede Zuordnung hinzu. Dieses Attribut gibt den Namen und den Namespace der Zuordnung, die Namen der Rollen in der Zuordnung, die Typen in der Zuordnung sowie die Multiplizität an jedem Ende der Zuordnung (z. B. 1:1 oder 1:n) an. Führen Sie dies unmittelbar über der Namespacedeklaration aus.
Fügen Sie EdmEntityTypeAttribute allen Klassen hinzu, denen ein Entitätstyp zugeordnet wurde.
Fügen Sie EdmScalarPropertyAttribute der Eigenschaft jeder Klasse hinzu, die einen Entitätsschlüssel für die eindeutige Identifizierung von Objekten darstellt. Geben Sie den Wert true für die EntityKeyProperty-Eigenschaft dieses Attributs an.
Fügen Sie den verbleibenden Eigenschaften EdmScalarPropertyAttribute hinzu. Geben Sie den Wert false für die IsNullable-Eigenschaft dieses Attributs an, wenn die Eigenschaft keine NULL-Werte akzeptiert.
Beispiel
In diesem Beispiel sind EDM-Attribute dargestellt, die auf die Order-Klasse und die LineItem-Klasse angewendet werden. Diese benutzerdefinierten Klassen werden der SalesOrderHeader-Tabelle und der SalesOrderDetail-Tabelle in der "AdventureWorks"-Datenbank zugeordnet. Beide Klassen erben von EntityObject.
Option Explicit On
Option Strict On
Imports System
Imports System.Data.SqlTypes
Imports System.Collections.Generic
Imports System.Text
Imports System.Data
Imports System.Data.Objects.DataClasses
Imports System.Data.Metadata.Edm
Imports Microsoft.Samples.Edm
<Assembly: EdmSchemaAttribute()>
<Assembly: EdmRelationshipAttribute("Microsoft.Samples.Edm", _
"FK_LineItem_Order_OrderId", "Order", _
RelationshipMultiplicity.One, GetType(Order), "LineItem", _
RelationshipMultiplicity.Many, GetType(LineItem))>
Namespace Microsoft.Samples.Edm
<EdmEntityTypeAttribute(NamespaceName:="Microsoft.Samples.Edm", Name:="Order")> _
Public Class Order
Inherits EntityObject
' Define private property variables.
Private _orderId As Integer
Private _orderDate As DateTime
Private _dueDate As DateTime
Private _shipDate As DateTime
Private _status As Byte
Private _customer As Integer
Private _subTotal As Decimal
Private _tax As Decimal
Private _freight As Decimal
Private _totalDue As Decimal
Private _extendedInfo As OrderInfo
'Default Constructor.
Sub New()
End Sub
' Public properties of the Order object.
<EdmScalarPropertyAttribute(EntityKeyProperty:=True, IsNullable:=False)> _
Public Property OrderId() As Integer
Get
Return _orderId
End Get
Set(ByVal value As Integer)
ReportPropertyChanging("OrderId")
_orderId = value
ReportPropertyChanged("OrderId")
End Set
End Property
' Navigation property that returns a collection of line items.
<EdmRelationshipNavigationPropertyAttribute("Microsoft.Samples.Edm", _
"FK_LineItem_Order_OrderId", "LineItem")> _
Public ReadOnly Property LineItem() As EntityCollection(Of LineItem)
Get
Return CType(Me, IEntityWithRelationships).RelationshipManager _
.GetRelatedCollection(Of LineItem) _
("FK_LineItem_Order_OrderId", "LineItem")
End Get
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property OrderDate() As Date
Get
Return _orderDate
End Get
Set(ByVal value As DateTime)
ReportPropertyChanging("OrderDate")
_orderDate = value
ReportPropertyChanged("OrderDate")
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property DueDate() As Date
Get
Return _dueDate
End Get
Set(ByVal value As Date)
ReportPropertyChanging("DueDate")
_dueDate = value
ReportPropertyChanged("DueDate")
End Set
End Property
<EdmScalarPropertyAttribute()> _
Public Property ShipDate() As Date
Get
Return _shipDate
End Get
Set(ByVal value As Date)
ReportPropertyChanging("ShipDate")
_shipDate = value
ReportPropertyChanged("ShipDate")
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Status() As Byte
Get
Return _status
End Get
Set(ByVal value As Byte)
If _status <> value Then
ReportPropertyChanging("Status")
_status = value
ReportPropertyChanged("Status")
End If
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Customer() As Integer
Get
Return _customer
End Get
Set(ByVal value As Integer)
ReportPropertyChanging("Customer")
_customer = value
ReportPropertyChanged("Customer")
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property SubTotal() As Decimal
Get
Return _subTotal
End Get
Set(ByVal value As Decimal)
If _subTotal <> value Then
' Validate the value before setting it.
If value < 0 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString, "SubTotal"))
End If
ReportPropertyChanging("SubTotal")
_subTotal = value
ReportPropertyChanged("SubTotal")
' Recalculate the order total.
CalculateOrderTotal()
End If
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property TaxAmt() As Decimal
Get
Return _tax
End Get
Set(ByVal value As Decimal)
' Validate the value before setting it.
If value < 0 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString(), "Tax"))
End If
ReportPropertyChanging("TaxAmt")
_tax = value
ReportPropertyChanged("TaxAmt")
' Recalculate the order total.
CalculateOrderTotal()
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Freight() As Decimal
Get
Return _freight
End Get
Set(ByVal value As Decimal)
If _freight <> value Then
' Validate the value before setting it.
If value < 0 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString(), "Freight"))
End If
ReportPropertyChanging("Freight")
_freight = value
ReportPropertyChanging("Freight")
' Recalculate the order total.
CalculateOrderTotal()
End If
End Set
End Property
Public ReadOnly Property TotalDue() As Decimal
Get
Return _totalDue
End Get
End Property
<EdmComplexPropertyAttribute()> _
Public Property ExtendedInfo() As OrderInfo
Get
Return _extendedInfo
End Get
Set(ByVal value As OrderInfo)
ReportPropertyChanging("ExtendedInfo")
_extendedInfo = value
ReportPropertyChanged("ExtendedInfo")
End Set
End Property
Private Sub CalculateOrderTotal()
' Update the total due as a sum of the other cost properties.
_totalDue = _subTotal + _tax + _freight
End Sub
End Class
<Global.System.Data.Objects.DataClasses.EdmComplexTypeAttribute( _
NamespaceName:="Microsoft.Samples.Edm", Name:="OrderInfo")> _
Partial Public Class OrderInfo
Inherits Global.System.Data.Objects.DataClasses.ComplexObject
Private _orderNumber As String
Private _purchaseOrder As String
Private _accountNumber As String
Private _comment As String
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property OrderNumber() As String
Get
Return _orderNumber
End Get
Set(ByVal value As String)
' Validate the value before setting it.
If value.Length > 25 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidString, _
"OrderNumber", "25"))
End If
ReportPropertyChanging("OrderNumber")
_orderNumber = value
ReportPropertyChanged("OrderNumber")
End Set
End Property
<EdmScalarPropertyAttribute()> _
Public Property PurchaseOrder() As String
Get
Return _purchaseOrder
End Get
Set(ByVal value As String)
' Validate the value before setting it.
If (value <> Nothing) AndAlso value.Length > 25 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidString, _
"PurchaseOrder", "25"))
End If
If _purchaseOrder <> value Then
ReportPropertyChanging("PurchaseOrder")
_purchaseOrder = value
ReportPropertyChanged("PurchaseOrder")
End If
End Set
End Property
<EdmScalarPropertyAttribute()> _
Public Property AccountNumber() As String
Get
Return _accountNumber
End Get
Set(ByVal value As String)
' Validate the value before setting it.
If (value <> Nothing) AndAlso value.Length > 15 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidString, _
"AccountNumber", "15"))
End If
ReportPropertyChanging("AccountNumber")
_accountNumber = value
ReportPropertyChanged("AccountNumber")
End Set
End Property
<EdmScalarPropertyAttribute()> _
Public Property Comment() As String
Get
Return _comment
End Get
Set(ByVal value As String)
' Validate the value before setting it.
If (value <> Nothing) AndAlso value.Length > 128 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidString, _
"Comment", "128"))
End If
If _comment <> value Then
ReportPropertyChanging("Comment")
_comment = value
ReportPropertyChanged("Comment")
End If
End Set
End Property
End Class
<EdmEntityTypeAttribute(NamespaceName:="Microsoft.Samples.Edm", _
Name:="LineItem")> _
Public Class LineItem
Inherits EntityObject
' Define private property variables.
Dim _lineItemId As Integer
Dim _trackingNumber As String
Dim _quantity As Short
Dim _product As Integer
Dim _price As Decimal
Dim _discount As Decimal
Dim _total As Decimal
Sub New()
End Sub
' Defines a navigation property to the Order class.
<EdmRelationshipNavigationPropertyAttribute("Microsoft.Samples.Edm", _
"FK_LineItem_Order_OrderId", "Order")> _
Public Property Order() As Order
Get
Return CType(Me, _
IEntityWithRelationships).RelationshipManager _
.GetRelatedReference(Of Order) _
("FK_LineItem_Order_OrderId", "Order").Value
End Get
Set(ByVal value As Order)
CType(Me, _
IEntityWithRelationships).RelationshipManager _
.GetRelatedReference(Of Order) _
("FK_LineItem_Order_OrderId", "Order").Value = value
End Set
End Property
<EdmScalarPropertyAttribute(EntityKeyProperty:=True, IsNullable:=False)> _
Public Property LineItemId() As Integer
Get
Return _lineItemId
End Get
Set(ByVal value As Integer)
ReportPropertyChanging("LineItemId")
_lineItemId = value
ReportPropertyChanged("LineItemId")
End Set
End Property
<EdmScalarPropertyAttribute()> _
Public Property TrackingNumber() As String
Get
Return _trackingNumber
End Get
Set(ByVal value As String)
If _trackingNumber <> value Then
' Validate the value before setting it.
If value.Length > 25 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidString, _
"TrackingNumber", "25"))
End If
ReportPropertyChanging("TrackingNumber")
_trackingNumber = value
ReportPropertyChanged("TrackingNumber")
End If
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Quantity() As Short
Get
Return _quantity
End Get
Set(ByVal value As Short)
If _quantity <> value Then
' Validate the value before setting it.
If value < 1 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString(), "Quantity"))
End If
ReportPropertyChanging("Quantity")
_quantity = value
ReportPropertyChanged("Quantity")
' Update the line total.
CalculateLineTotal()
End If
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Product() As Integer
Get
Return _product
End Get
Set(ByVal value As Integer)
' Validate the value before setting it.
If value < 1 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString(), "Product"))
End If
ReportPropertyChanging("Product")
_product = value
ReportPropertyChanged("Product")
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Price() As Decimal
Get
Return _price
End Get
Set(ByVal value As Decimal)
If _price <> value Then
' Validate the value before setting it.
If value < 0 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString(), "Price"))
End If
ReportPropertyChanging("Price")
_price = value
ReportPropertyChanged("Price")
' Update the line total.
CalculateLineTotal()
End If
End Set
End Property
<EdmScalarPropertyAttribute(IsNullable:=False)> _
Public Property Discount() As Decimal
Get
Return _discount
End Get
Set(ByVal value As Decimal)
' Validate the value before setting it.
If value < 0 Then
Throw New ApplicationException(String.Format( _
My.Resources.propertyNotValidNegative, _
value.ToString(), "Discount"))
End If
ReportPropertyChanging("Discount")
_discount = value
ReportPropertyChanged("Discount")
End Set
End Property
Public ReadOnly Property Total() As Decimal
Get
Return _total
End Get
End Property
Private Sub CalculateLineTotal()
_total = (_quantity * (_price - _discount))
End Sub
End Class
End Namespace
using System;
using System.Data.SqlTypes;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.Objects.DataClasses;
using System.Data.Metadata.Edm;
using Microsoft.Samples.Edm;
[assembly: EdmSchemaAttribute()]
[assembly: EdmRelationshipAttribute("Microsoft.Samples.Edm",
"FK_LineItem_Order_OrderId", "Order",
RelationshipMultiplicity.One, typeof(Order),"LineItem",
RelationshipMultiplicity.Many, typeof(LineItem))]
namespace Microsoft.Samples.Edm
{
[EdmEntityTypeAttribute(NamespaceName="Microsoft.Samples.Edm",Name="Order")]
public class Order : EntityObject
{
// Define private property variables.
private int _orderId;
private DateTime _orderDate;
private DateTime _dueDate;
private DateTime _shipDate;
private byte _status;
private int _customer;
private decimal _subTotal;
private decimal _tax;
private decimal _freight;
private decimal _totalDue;
private OrderInfo _ExtendedInfo;
// Public properties of the Order object.
[EdmScalarPropertyAttribute(EntityKeyProperty = true, IsNullable = false)]
public int OrderId
{
get
{
return _orderId;
}
set
{
ReportPropertyChanging("OrderId");
_orderId = value;
ReportPropertyChanged("OrderId");
}
}
// Navigation property that returns a collection of line items.
[EdmRelationshipNavigationPropertyAttribute("Microsoft.Samples.Edm","FK_LineItem_Order_OrderId", "LineItem")]
public System.Data.Objects.DataClasses.EntityCollection<LineItem> LineItem
{
get
{
return ((IEntityWithRelationships)(this)).RelationshipManager.
GetRelatedCollection<LineItem>("FK_LineItem_Order_OrderId", "LineItem");
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public DateTime OrderDate
{
get
{
return _orderDate;
}
set
{
ReportPropertyChanging("OrderDate");
_orderDate = value;
ReportPropertyChanged("OrderDate");
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public DateTime DueDate
{
get
{
return _dueDate;
}
set
{
ReportPropertyChanging("DueDate");
_dueDate = value;
ReportPropertyChanged("DueDate");
}
}
[EdmScalarPropertyAttribute()]
public DateTime ShipDate
{
get
{
return _shipDate;
}
set
{
ReportPropertyChanging("ShipDate");
_shipDate = value;
ReportPropertyChanged("ShipDate");
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public byte Status
{
get
{
return _status;
}
set
{
if (_status != value)
{
ReportPropertyChanging("Status");
_status = value;
ReportPropertyChanged("Status");
}
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public int Customer
{
get
{
return _customer;
}
set
{
ReportPropertyChanging("Customer");
_customer = value;
ReportPropertyChanged("Customer");
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public decimal SubTotal
{
get
{
return _subTotal;
}
set
{
if (_subTotal != value)
{
// Validate the value before setting it.
if (value < 0)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "SubTotal" }));
}
ReportPropertyChanging("SubTotal");
_subTotal = value;
ReportPropertyChanged("SubTotal");
// Recalculate the order total.
CalculateOrderTotal();
}
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public decimal TaxAmt
{
get
{
return _tax;
}
set
{
// Validate the value before setting it.
if (value < 0)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "Tax" }));
}
ReportPropertyChanging("TaxAmt");
_tax = value;
ReportPropertyChanged("TaxAmt");
// Recalculate the order total.
CalculateOrderTotal();
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public decimal Freight
{
get
{
return _freight;
}
set
{
if (_freight != value)
{
// Validate the value before setting it.
if (value < 0)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "Freight" }));
}
ReportPropertyChanging("Freight");
_freight = value;
ReportPropertyChanging("Freight");
// Recalculate the order total.
CalculateOrderTotal();
}
}
}
public decimal TotalDue
{
get
{
return _totalDue;
}
}
[EdmComplexPropertyAttribute()]
public OrderInfo ExtendedInfo
{
get
{
return _ExtendedInfo;
}
set
{
this.ReportPropertyChanging("ExtendedInfo");
_ExtendedInfo = value;
this.ReportPropertyChanged("ExtendedInfo");
}
}
private void CalculateOrderTotal()
{
// Update the total due as a sum of the other cost properties.
_totalDue = _subTotal + _tax + _freight;
}
}
[EdmComplexTypeAttribute(NamespaceName =
"Microsoft.Samples.Edm", Name = "OrderInfo")]
public partial class OrderInfo : ComplexObject
{
private string _orderNumber;
private string _purchaseOrder;
private string _accountNumber;
private string _comment;
[EdmScalarPropertyAttribute(IsNullable = false)]
public string OrderNumber
{
get
{
return _orderNumber;
}
set
{
// Validate the value before setting it.
if (value.Length > 25)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidString,
new string[3] { value, "OrderNumber", "25" }));
}
ReportPropertyChanging("OrderNumber");
_orderNumber = value;
ReportPropertyChanged("OrderNumber");
}
}
[EdmScalarPropertyAttribute()]
public string PurchaseOrder
{
get
{
return _purchaseOrder;
}
set
{
// Validate the value before setting it.
if ((value != null) && value.Length > 25)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidString,
new string[3] { value, "PurchaseOrder", "25" }));
}
if (_purchaseOrder != value)
{
ReportPropertyChanging("PurchaseOrder");
_purchaseOrder = value;
ReportPropertyChanged("PurchaseOrder");
}
}
}
[EdmScalarPropertyAttribute()]
public string AccountNumber
{
get
{
return _accountNumber;
}
set
{
// Validate the value before setting it.
if ((value != null) && value.Length > 15)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidString,
new string[3] { value, "AccountNumber", "15" }));
}
ReportPropertyChanging("AccountNumber");
_accountNumber = value;
ReportPropertyChanged("AccountNumber");
}
}
[EdmScalarPropertyAttribute()]
public string Comment
{
get
{
return _comment;
}
set
{
// Validate the value before setting it.
if ((value != null) && value.Length > 128)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidString,
new string[3] { value, "Comment", "128" }));
}
if (_comment != value)
{
ReportPropertyChanging("Comment");
_comment = value;
ReportPropertyChanged("Comment");
}
}
}
}
[EdmEntityTypeAttribute(NamespaceName = "Microsoft.Samples.Edm", Name = "LineItem")]
public class LineItem : EntityObject
{
// Define private property variables.
int _lineItemId;
string _trackingNumber;
short _quantity;
int _product;
decimal _price;
decimal _discount;
decimal _total;
// Default constructor.
public LineItem()
{
}
// Defines a navigation property to the Order class.
[EdmRelationshipNavigationPropertyAttribute("Microsoft.Samples.Edm", "FK_LineItem_Order_OrderId", "Order")]
public Order Order
{
get
{
return ((IEntityWithRelationships)(this)).RelationshipManager.
GetRelatedReference<Order>("FK_LineItem_Order_OrderId", "Order").Value;
}
set
{
((IEntityWithRelationships)(this)).RelationshipManager.
GetRelatedReference<Order>("FK_LineItem_Order_OrderId", "Order").Value = value;
}
}
[EdmScalarPropertyAttribute(EntityKeyProperty = true, IsNullable = false)]
public int LineItemId
{
get
{
return _lineItemId;
}
set
{
ReportPropertyChanging("LineItemId");
_lineItemId = value;
ReportPropertyChanged("LineItemId");
}
}
[EdmScalarPropertyAttribute()]
public string TrackingNumber
{
get
{
return _trackingNumber;
}
set
{
if (_trackingNumber != value)
{
// Validate the value before setting it.
if (value.Length > 25)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidString,
new string[3] {value,"TrackingNumber", "25"}));
}
ReportPropertyChanging("TrackingNumber");
_trackingNumber = value;
ReportPropertyChanged("TrackingNumber");
}
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public short Quantity
{
get
{
return _quantity;
}
set
{
if (_quantity != value)
{
// Validate the value before setting it.
if (value < 1)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "Quantity" }));
}
ReportPropertyChanging("Quantity");
_quantity = value;
ReportPropertyChanged("Quantity");
// Update the line total.
CalculateLineTotal();
}
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public int Product
{
get
{
return _product;
}
set
{
// Validate the value before setting it.
if (value < 1)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "Product" }));
}
ReportPropertyChanging("Product");
_product = value;
ReportPropertyChanged("Product");
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public decimal Price
{
get
{
return _price;
}
set
{
if (_price != value)
{
// Validate the value before setting it.
if (value < 0)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "Price" }));
}
ReportPropertyChanging("Price");
_price = value;
ReportPropertyChanged("Price");
// Update the line total.
CalculateLineTotal();
}
}
}
[EdmScalarPropertyAttribute(IsNullable = false)]
public decimal Discount
{
get
{
return _discount;
}
set
{
// Validate the value before setting it.
if (value < 0)
{
throw new ApplicationException(string.Format(
Properties.Resources.propertyNotValidNegative,
new string[2] { value.ToString(), "Discount" }));
}
ReportPropertyChanging("Discount");
_discount = value;
ReportPropertyChanged("Discount");
}
}
public decimal Total
{
get
{
return _total;
}
}
private void CalculateLineTotal()
{
_total = (_quantity * (_price - _discount));
}
}
}
Siehe auch
Aufgaben
Gewusst wie: Verwenden von Object Services mit benutzerdefinierten Objekten (Entity Framework)
Konzepte
Anpassen von Objekten (Entity Framework)
Weitere Ressourcen
Arbeiten mit benutzerdefinierten Objekten (Entity Framework-Aufgaben)