Gets whether the collection has been locked for updating.
true if the collection is locked; otherwise, false.
The CustomFieldCollection.BeginUpdate and CustomFieldCollection.EndUpdate methods use an internal counter to implement the appropriate functionality. The counter's initial value is 0. The BeginUpdate method increments the counter. EndUpdate decrements the counter, and if its new value is zero, change notifications are enabled. Note that each call to BeginUpdate must be paired with a call to EndUpdate. If BeginUpdate is called but without a subsequent call to EndUpdate, or it's not called because an exception occurred, the collection will no longer be updated. To ensure that EndUpdate is always called even if an exception occurs, use a try...finally statement.