WorkflowEventArgs.WorkflowInstance Property

Definition

Namespace:

System.Workflow.Runtime

Assembly:

System.Workflow.Runtime.dll

Gets the workflow instance associated with the workflow event.

public:
 property System::Workflow::Runtime::WorkflowInstance ^ WorkflowInstance { System::Workflow::Runtime::WorkflowInstance ^ get(); };

public System.Workflow.Runtime.WorkflowInstance WorkflowInstance { get; }

member this.WorkflowInstance : System.Workflow.Runtime.WorkflowInstance

Public ReadOnly Property WorkflowInstance As WorkflowInstance

Property Value

WorkflowInstance

The WorkflowInstance associated with the workflow event.

Examples

The following code example demonstrates how to obtain a WorkflowInstance object using the WorkflowInstance property when an event handler method is called. When the WorkflowIdled event occurs, the OnWorkflowIdled method defined in this example is called. It determines which workflow is idled using the WorkflowInstance property and then gets a collection of queued items for the workflow instance by calling the GetWorkflowQueueData method. The code iterates over the collection to determine which activity is waiting for the event that idled the workflow. It then sends an exception to the workflow queue using the EnqueueItem method along with the name of the event queue item.

This code example is part of the Canceling a Workflow SDK Sample from the Program.cs file. For more information, see Canceling a Workflow.

static void OnWorkflowIdled(object sender, WorkflowEventArgs e)
{
    WorkflowInstance workflow = e.WorkflowInstance;

    Console.WriteLine("\n...waiting for 3 seconds... \n");
    Thread.Sleep(3000);

    // what activity is blocking the workflow
    ReadOnlyCollection<WorkflowQueueInfo> wqi = workflow.GetWorkflowQueueData();
    foreach (WorkflowQueueInfo q in wqi)
    {
        EventQueueName eq = q.QueueName as EventQueueName;
        if (eq != null)
        {
            // get activity that is waiting for event
            ReadOnlyCollection<string> blockedActivity = q.SubscribedActivityNames;
            Console.WriteLine("Host: Workflow is blocked on " + blockedActivity[0]);

            // this event is never going to arrive eg. employee left the company
            // lets send an exception to this queue
            // it will either be handled by exception handler that was modeled in workflow
            // or the runtime will unwind running compensation handlers and exit the workflow
            Console.WriteLine("Host: This event is not going to arrive");
            Console.WriteLine("Host: Cancel workflow with unhandled exception");
            workflow.EnqueueItem(q.QueueName, new Exception("ExitWorkflowException"), null, null);
        }
    }
}

Shared Sub OnWorkflowIdled(ByVal sender As Object, ByVal e As WorkflowEventArgs)
    Dim workflow As WorkflowInstance = e.WorkflowInstance

    Console.WriteLine(vbCrLf + "...waiting for 3 seconds... " + vbCrLf)
    Thread.Sleep(3000)

    ' what activity is blocking the workflow
    Dim wqi As ReadOnlyCollection(Of WorkflowQueueInfo) = workflow.GetWorkflowQueueData()
    For Each q As WorkflowQueueInfo In wqi

        Dim eq As EventQueueName = TryCast(q.QueueName, EventQueueName)

        If eq IsNot Nothing Then
            ' get activity that is waiting for event
            Dim blockedActivity As ReadOnlyCollection(Of String) = q.SubscribedActivityNames
            Console.WriteLine("Host: Workflow is blocked on " + blockedActivity(0))

            ' this event is never going to arrive eg. employee left the company
            ' lets send an exception to this queue
            ' it will either be handled by exception handler that was modeled in workflow
            ' or the runtime will unwind running compensation handlers and exit the workflow
            Console.WriteLine("Host: This event is not going to arrive")
            Console.WriteLine("Host: Cancel workflow with unhandled exception")
            workflow.EnqueueItem(q.QueueName, New Exception("ExitWorkflowException"), Nothing, Nothing)
        End If
    Next
End Sub

See also

• Canceling a Workflow