如何：从 EntityObject 和 ComplexObject 基类继承（实体框架）
当您将自定义数据类用于 实体数据模型 (EDM) 时，必须更新自定义数据类以从 EntityObject 和 ComplexObject 继承。还必须应用 EDM 属性 (Attribute)，这些属性将自定义类和属性 (Property) 映射到在概念性架构定义语言 (CSDL) 文件中定义的实体类型和复杂类型。有关更多信息，请参见如何：将自定义对象映射到实体（实体框架）。
还可以实现自定义数据类接口，而不从 EntityObject 或 ComplexObject 继承。有关更多信息，请参见实现自定义数据类接口（实体框架）。
从 EntityObject 继承
修改每个自定义数据类的定义，以便它从 EntityObject 继承，如以下示例所示：
<EdmEntityTypeAttribute(NamespaceName:="Microsoft.Samples.Edm", Name:="Order")> _ Public Class Order Inherits EntityObject[EdmEntityTypeAttribute(NamespaceName="Microsoft.Samples.Edm",Name="Order")] public class Order : EntityObject在每个数据类的可设置的标量属性中，在设置 ReportPropertyChanging 属性的值之前添加对此属性的调用，并在设置 ReportPropertyChanged 属性之后添加对此属性的调用。下面的示例对此进行了演示：
Set(ByVal value As Integer) ReportPropertyChanging("OrderId") _orderId = value ReportPropertyChanged("OrderId") End Setset { ReportPropertyChanging("OrderId"); _orderId = value; ReportPropertyChanged("OrderId"); }
从 ComplexObject 继承
修改每个自定义复杂数据类的定义，以便该类从 ComplexObject 继承，如下面的示例中所示：
<Global.System.Data.Objects.DataClasses.EdmComplexTypeAttribute( _ NamespaceName:="Microsoft.Samples.Edm", Name:="OrderInfo")> _ Partial Public Class OrderInfo Inherits Global.System.Data.Objects.DataClasses.ComplexObject[EdmComplexTypeAttribute(NamespaceName = "Microsoft.Samples.Edm", Name = "OrderInfo")] public partial class OrderInfo : ComplexObject在每个复杂数据类的可设置的标量属性中，在设置 ReportPropertyChanging 属性的值之前添加对此属性的调用，并在设置 ReportPropertyChanged 属性之后添加对此属性的调用。下面的示例对此进行了演示：
' 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// 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"); }
示例
本示例演示自定义数据类 Order 和 LineItem 以及复杂数据类 OrderInfo。这些自定义类映射到 AdventureWorks 数据库中的 SalesOrderHeader 和 SalesOrderDetail 表。Order 和 LineItem 类继承自 EntityObject，而 OrderInfo 复杂数据类继承自 ComplexObject。
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));
}
}
}
另请参见
任务
如何：自定义实体数据模型以使用自定义对象（实体框架）
如何：实现自定义数据类接口（实体框架）