ExternalDataExchangeAttribute Class (System.Workflow.Activities)

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.NET Framework Class Library
ExternalDataExchangeAttribute Class

Marks an interface as a local service interface. This class cannot be inherited.

Inheritance Hierarchy

System.Object
  System.Attribute
    System.Workflow.Activities.ExternalDataExchangeAttribute

Namespace:  System.Workflow.Activities
Assembly:  System.Workflow.Activities (in System.Workflow.Activities.dll)
Syntax

Visual Basic
<AttributeUsageAttribute(AttributeTargets.Interface, AllowMultiple := False,  _
	Inherited := False)> _
Public NotInheritable Class ExternalDataExchangeAttribute _
	Inherits Attribute
C#
[AttributeUsageAttribute(AttributeTargets.Interface, AllowMultiple = false, 
	Inherited = false)]
public sealed class ExternalDataExchangeAttribute : Attribute
Visual C++
[AttributeUsageAttribute(AttributeTargets::Interface, AllowMultiple = false, 
	Inherited = false)]
public ref class ExternalDataExchangeAttribute sealed : public Attribute
F#
[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Interface, AllowMultiple = false, 
    Inherited = false)>]
type ExternalDataExchangeAttribute =  
    class
        inherit Attribute
    end

The ExternalDataExchangeAttribute type exposes the following members.

Constructors

  Name Description
Public method ExternalDataExchangeAttribute Initializes a new instance of the ExternalDataExchangeAttribute.
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Properties

  Name Description
Public property TypeId When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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Methods

  Name Description
Public method Equals Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Returns the hash code for this instance. (Inherited from Attribute.)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttribute When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method Match When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
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Explicit Interface Implementations

  Name Description
Explicit interface implemetation Private method _Attribute.GetIDsOfNames Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfo Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.GetTypeInfoCount Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _Attribute.Invoke Provides access to properties and methods exposed by an object. (Inherited from Attribute.)
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Remarks

A class that implements a local service interface must be added to the ExternalDataExchangeService and can be used by CallExternalMethodActivity and HandleExternalEventActivity.

Events on interfaces that are attributed with ExternalDataExchangeAttribute should have event data that derive from ExternalDataEventArgs.

While generic types are supported for interface method and event declarations, generic types are not supported for the interface declaration itself. The following interface would not be valid for use as an ExternalDataExchange.

public interface IInterfaceName<TCommand>
{ 
    void MethodName(TCommand Request);
}
Examples

The following code example shows how to set the ExternalDataExchangeAttribute on an interface. This code example is part of the ActiveDirectoryRoles SDK sample from the IStartPurchaseOrder.cs file. For more information, seeUsing Active Directory Roles.

C#

[ExternalDataExchangeAttribute()]
public interface IStartPurchaseOrder
{
    event EventHandler<InitiatePOEventArgs> InitiatePurchaseOrder;
}


Version Information

.NET Framework

Supported in: 4, 3.5, 3.0
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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.
See Also

Reference