A common way to use these collections is to HTML-encode the values supplied by the user before they are stored in the data source. For more information about handling events, see NIB: Consuming Events.
I've found an answer in other forum, and though I didn't find the code of Form View, I've found a Details View implementation and I think in this case it might be similar.
A Details View Update Event Args object is passed to the event handler, which allows you to determine the index of the record being updated and to indicate that the update operation should be canceled.
To cancel the update operation, set the collections, if necessary, before the values are passed to the data source.
In either case I guess, it's more of a state change than the raising of events.
[Updated] I think what we are both saying is that if no one has subscribed to the event (i.e., no one is listening for it), there's no point in raising it.
" The Details View control is not limited to exposing its data to users in an appropriate and friendly way.
The control also provides interactive buttons to navigate data and edit and insert new records.
I’m usually disappointed when writers employ oft-overused metaphors to describe a situation.These features are provided out-of-the-box and are not configurable by programmers.Or, at least, not declaratively and, maybe, not easily.You shouldn't have to explicitly call fw Hotel Details. This event is raised when a Form View control attempts to switch between edit, insert, and read-only mode, but before the mode actually changes. The Details View control has in its Events an Item Command event that uses the Details View Command Event Args event arg class which has a Command Name property. Cancel = true and the "ed" events have redirects to send the user back to a list page that shows the items they just added/updated/deleted.