You create a Windows Workflow Foundation application by using Microsoft .NET Framework 3.5. A Windows Forms application functions as the workflow host by using the DefaultWorkflowSchedulerService. You create a WorkflowRuntime instance in the Load event of the forms. You also subscribe to the WorkflowCompleted event. You need to ensure that the application displays the message in the Label control named lblStatus when the WorkflowCompleted event is raised.
Which code segment should you use?
A.
private void UpdateInstances(Guid id) { if (this.InvokeRequired) { lblStatus.Text = id + " completed"; }}
B.
private void UpdateInstances(Guid id) { if (!this.InvokeRequired) { lblStatus.Text = id + " completed"; }}
C.
delegate void UpdateInstancesDelegate(Guid id);private void UpdateInstances(Guid id) { if (this.InvokeRequired) { this.Invoke( new UpdateInstancesDelegate(UpdateInstances), new object[] { id }); } else { lblStatus.Text = id + " completed"; }}
D.
delegate void UpdateInstancesDelegate(Guid id);private void UpdateInstances(Guid id) { if (!this.InvokeRequired) { this.Invoke( new UpdateInstancesDelegate(UpdateInstances), new object[] { id }); } else { lblStatus.Text = id + " completed"; }}