Itemupdating vs itemupdated
The trigger may come from manual action (updating item manually) or automatic action (SPItem. These events many go infinitely and impact the server performance majorly.To avoid this unnecessary event firing, we can purposely enable/disable the other event firing on the same object.But make sure that your custom code is not using Run With Elevated Previllege method.Sandbox solution only can access the site collection object and it cannot access other than site collection object, network resources, database Its based on requirement.This provides an opportunity for an event receiver to perform tasks before data is committed to a database.A good example of the use of Before events is performing data validation, because Before events fire prior to commitment of data.Each event host type has a specific set of event receiver base types from which it can inherit.1.Syncronous Events: This event is executed in the same thread in which the triggering action is occurring.
These events are asynchronous because they need not happen immediately after the event is performed. SPWeb Event Receiver : This provides event handling whenever a site or a site collection is deleted or moved Site Deleted – This occurs after a site collection is deleted.
For example, when a new item is added to a list, we may need to perform some action like say, notifying the person who created the list item, or modifying the dependent entries in some other location etc.
Handling of such events is facilitated by event receivers.
event receivers bound to the same list (one from Assembly "1" and the other from Assembly "2"), the event receiver that is bound with a lower sequence number is executed first.
A practical example is adding an event receiver to a system list that already has a system event receiver bound to it.