This documentation is archived and is not being maintained.

EventDeliveryFailedException Class

The exception that is thrown when an event that is raised from the host cannot be delivered to the workflow instance. Typically the event is raised from an ExternalDataExchangeService on a workflow instance. This class cannot be inherited.

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

public sealed class EventDeliveryFailedException : SystemException

The following string is added to the event log when this exception is thrown: Event "{1}" on interface type "{0}" for instance id "{2}" cannot be delivered.

When using a state machine workflow, you might get an exception with the message "Queue '{0}' is not enabled." This happens when the current state of the state machine does not know how to handle a specific event. For example, when some state other than the current state contains the EventDrivenActivity that contains the HandleExternalEventActivity that is represented by the queue '{0}'.


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

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0