WorkflowRuntime.ServicesExceptionNotHandled Event

Occurs when a service that is derived from the WorkflowRuntimeService class calls RaiseServicesExceptionNotHandledEvent.

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

public event EventHandler<ServicesExceptionNotHandledEventArgs> ServicesExceptionNotHandled

A service that is derived from the WorkflowRuntimeService class can call the RaiseServicesExceptionNotHandledEvent method in order to inform subscribers to the ServicesExceptionNotHandled event that an exception that it was unable to handle occurred during its execution. You can subscribe to this event in order to implement a recovery mechanism.

This event is raised when a workflow instance has not been created yet by the workflow runtime engine and an exception occurs. In this scenario, the only way to inform a host application that an exception occurred is to raise this event. However, the workflow runtime engine does not call this directly. Instead, the workflow runtime engine either delivers an exception to the workflow instance or, if there is no instance, throws back to the caller, which in this case is actually the service that fires this event. If you create your own persistence or scheduler service, you will need to implement this event yourself through the base RaiseServicesExceptionNotHandledEvent method.

For the ServicesExceptionNotHandled event, sender will contain the WorkflowRuntime and WorkflowEventArgs will contain the Guid of the workflow instance that was using the service and the Exception that could not be handled.

For more information about handling events, see Consuming Events.

The following code example demonstrates how you can use WorkflowRuntime functionality from a workflow host. The code associates the ServicesExceptionNotHandled with an event handler, a method named OnExceptionNotHandled.

This code example is part of the Custom Persistence Service SDK sample from the Program.cs file. For more information, see Custom Persistence Service.

static void Main()
{
    using (WorkflowRuntime workflowRuntime = new WorkflowRuntime())
    {
        try
        {
            // engine will unload workflow instance when it is idle
            workflowRuntime.AddService(new FilePersistenceService(true));

            workflowRuntime.WorkflowCreated += OnWorkflowCreated;
            workflowRuntime.WorkflowCompleted += OnWorkflowCompleted;
            workflowRuntime.WorkflowIdled += OnWorkflowIdle;
            workflowRuntime.WorkflowUnloaded += OnWorkflowUnload;
            workflowRuntime.WorkflowLoaded += OnWorkflowLoad;
            workflowRuntime.WorkflowTerminated += OnWorkflowTerminated;
            workflowRuntime.ServicesExceptionNotHandled += OnExceptionNotHandled;

            workflowRuntime.CreateWorkflow(typeof(PersistenceServiceWorkflow)).Start();

            waitHandle.WaitOne();
        }
        catch (Exception e)
        {
            Console.WriteLine("Exception \n\t Source: {0} \n\t Message: {1}", e.Source, e.Message);
        }
        finally
        {
            workflowRuntime.StopRuntime();
            Console.WriteLine("Workflow runtime stopped, program exiting... \n");
        }
    }
}

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
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