Handles the asynchronous event that occurs after an attachment is added to an item.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
This event occurs when an attachment is added to a list item, but no other updates occur. The event occurs after the ItemUpdated event if other changes are made to the item.
Before and After properties are guaranteed for postback events on documents, but Before properties are not available for postback events on list items.