ExternalReferenceAttribute Class

Article
01/27/2012

[WCF RIA Services Version 1 Service Pack 2 is compatible with either .NET framework 4 or .NET Framework 4.5, and with either Silverlight 4 or Silverlight 5.]

Indicates that an association references entities belonging to an external DomainContext.

Inheritance Hierarchy

System.Object
System.Attribute
System.ServiceModel.DomainServices.ExternalReferenceAttribute

Namespace: System.ServiceModel.DomainServices
Assembly: System.ServiceModel.DomainServices.Client (in System.ServiceModel.DomainServices.Client.dll)

Syntax

'Declaration
<AttributeUsageAttribute(AttributeTargets.Property Or AttributeTargets.Field, AllowMultiple := False,  _
    Inherited := True)> _
Public NotInheritable Class ExternalReferenceAttribute _
    Inherits Attribute

'Usage
Dim instance As ExternalReferenceAttribute

[AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Field, AllowMultiple = false, 
    Inherited = true)]
public sealed class ExternalReferenceAttribute : Attribute

[AttributeUsageAttribute(AttributeTargets::Property|AttributeTargets::Field, AllowMultiple = false, 
    Inherited = true)]
public ref class ExternalReferenceAttribute sealed : public Attribute

[<SealedAttribute>]
[<AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Field, AllowMultiple = false, 
    Inherited = true)>]
type ExternalReferenceAttribute =  
    class
        inherit Attribute
    end

public final class ExternalReferenceAttribute extends Attribute

The ExternalReferenceAttribute type exposes the following members.

Constructors

	Name	Description
	ExternalReferenceAttribute	Initializes a new instance of the ExternalReferenceAttribute class.

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Properties

	Name	Description
	TypeId	(Inherited from Attribute.)

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Methods

	Name	Description
	Equals	(Inherited from Attribute.)
	Finalize	(Inherited from Object.)
	GetHashCode	(Inherited from Attribute.)
	GetType	(Inherited from Object.)
	IsDefaultAttribute	(Inherited from Attribute.)
	Match	(Inherited from Attribute.)
	MemberwiseClone	(Inherited from Object.)
	ToString	(Inherited from Object.)

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Explicit Interface Implementations

	Name	Description
	_Attribute.GetIDsOfNames	(Inherited from Attribute.)
	_Attribute.GetTypeInfo	(Inherited from Attribute.)
	_Attribute.GetTypeInfoCount	(Inherited from Attribute.)
	_Attribute.Invoke	(Inherited from Attribute.)

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Remarks

When applied to an entity association member, this attribute indicates that the framework should not create a corresponding EntitySet in the generated client-side code. Consumers of the client-side property will need to add a DomainContext reference to the appropriate DomainContext containing the external entity type.

For a complete example, see Walkthrough: Sharing Entities between Multiple Domain Services.

Examples

The following example shows an ExternalReference attribute applied to a member that defines a related entity from another domain service.

Imports System.ServiceModel.DomainServices
Imports System.ComponentModel.DataAnnotations

Partial Public Class SalesOrderHeader
    <ExternalReference()> _
    <Association("Sales_Customer", "CustomerID", "CustomerID")> _
    Public Property Customer() As Customer

End Class

using System;
using System.ServiceModel.DomainServices;
using System.ComponentModel.DataAnnotations;

namespace SharedEntityExample.Web
{
    public partial class SalesOrderHeader
    {
        [ExternalReference]
        [Association("Sales_Customer", "CustomerID", "CustomerID")]
        public Customer Customer { get; set; }
    }
}

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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