Cannot reuse a trigger?

[Ebola-Chan-bot]

Shared ReadOnly ValidTriggers As Trigger() = {New DailyTrigger(1), New DailyTrigger(2), New DailyTrigger(4), New WeeklyTrigger(1), New WeeklyTrigger(2), New MonthlyTrigger(1)}

I provide a ComboBox for the user to select a trigger to use. I get its SelectedIndex and use the index to get the corresponding trigger in a preloaded triggers array, and then add a task with this trigger. However, if the user select the same trigger twice, it throws NullReferenceException.
Is the trigger broken after being sent into a task?

[dahall]

Yes. I would use the Clone method on the trigger before adding it to the Triggers of the task.

task.Defnition.Triggers.Add((Trigger)ValidTriggers[selectedIndex].Clone());