WorkflowApplicationUnhandledExceptionEventArgs Class

Definition

Namespace:

System.Activities

Assembly:

System.Activities.dll

Provides information about an unhandled exception that occurred in a workflow instance.

public ref class WorkflowApplicationUnhandledExceptionEventArgs : System::Activities::WorkflowApplicationEventArgs

public class WorkflowApplicationUnhandledExceptionEventArgs : System.Activities.WorkflowApplicationEventArgs

type WorkflowApplicationUnhandledExceptionEventArgs = class
    inherit WorkflowApplicationEventArgs

Public Class WorkflowApplicationUnhandledExceptionEventArgs
Inherits WorkflowApplicationEventArgs

Inheritance

Object

EventArgs

WorkflowApplicationEventArgs

WorkflowApplicationUnhandledExceptionEventArgs

Examples

The following example invokes a workflow that throws an exception. The exception is unhandled by the workflow and the OnUnhandledException handler is invoked. The WorkflowApplicationUnhandledExceptionEventArgs are inspected to provide information about the exception, and the workflow is terminated.

Activity wf = new Sequence
{
    Activities =
     {
         new WriteLine
         {
             Text = "Starting the workflow."
         },
         new Throw
        {
            Exception = new InArgument<Exception>((env) =>
                new ApplicationException("Something unexpected happened."))
        },
        new WriteLine
         {
             Text = "Ending the workflow."
         }
     }
};

WorkflowApplication wfApp = new WorkflowApplication(wf);

wfApp.OnUnhandledException = delegate(WorkflowApplicationUnhandledExceptionEventArgs e)
{
    // Display the unhandled exception.
    Console.WriteLine("OnUnhandledException in Workflow {0}\n{1}",
        e.InstanceId, e.UnhandledException.Message);

    Console.WriteLine("ExceptionSource: {0} - {1}",
        e.ExceptionSource.DisplayName, e.ExceptionSourceInstanceId);

    // Instruct the runtime to terminate the workflow.
    return UnhandledExceptionAction.Terminate;

    // Other choices are UnhandledExceptionAction.Abort and
    // UnhandledExceptionAction.Cancel
};

wfApp.Run();

Remarks

If an exception is thrown by an activity and is unhandled, the default behavior is to terminate the workflow instance. If an OnUnhandledException handler is present, it can override this default behavior. This handler gives the workflow host author an opportunity to provide the appropriate handling, such as custom logging, aborting the workflow, canceling the workflow, or terminating the workflow.

Properties

ExceptionSource	Gets the activity that is the source of the unhandled exception.
ExceptionSourceInstanceId	Gets the unique identifier of the activity instance that is the source of the unhandled exception.
InstanceId	The unique identifier of the workflow instance. (Inherited from WorkflowApplicationEventArgs)
UnhandledException	Gets the Exception that was unhandled by the workflow instance.

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetInstanceExtensions<T>()	Gets the collection of extensions of the specified type. (Inherited from WorkflowApplicationEventArgs)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)