The ActionBase.BeginUpdate and EndUpdate methods are designed to implement batch modifications with the current Action. This allows you to prevent excessive updates when changing multiple settings at once. For this purpose, enclose the code that changes the properties within calls to these methods.
The BeginUpdate and EndUpdate methods use an internal counter to implement their functionality. The counter's initial value is 0. The current lock count is returned by the ActionBase.LockCount property. A call to the BeginUpdate method increments the counter by one. A call to the EndUpdate method decrements the counter by one, and if its new value is zero, a change notification is generated. This means that each call to BeginUpdate must be paired with a call to EndUpdate. If a call to BeginUpdate is made but without a corresponding call to EndUpdate afterwards or EndUpdate is not called because an exception occurred, the Action will no longer respond to changes. To ensure that EndUpdate is always called even if an exception occurs, wrap any calls to these methods in a try...finally statement.