This blog post by fellow SharePoint MVP, Randy Williams has always been a good reference for me when working with SharePoint 2007 event receivers. I have decided to test Randy’s finding against SharePoint 2010 and extend his great work by taking into account the newly introduced “Post Synchronous” events.
The following table summarizes how Synchronous, Asynchronous and Post Synchronous events work with lists and libraries in SharePoint 2010.
| List | BeforePropoerties | AfterProperties | properties.ListItem |
| ItemAdding | No value | New value | Null |
| ItemAdded | No value | New value | New value |
| ItemAdded – sync | No value | New value | New value |
| ItemUpdating | No value | Changed value | Original value |
| ItemUpdated | No value | Changed value | Changed value |
| ItemUpdated – sync | No value | Changed value | Changed value |
| ItemDeleting | No value | No value | Original value |
| ItemDeleted | No value | No value | Null |
| ItemDeleted – sync | No value | No value | Null |
| Library | BeforePropoerties | AfterProperties | properties.ListItem |
| ItemAdding | No value | No value | New value |
| ItemAdded | No value | No value | New value |
| ItemAdded – sync | No value | No value | New value |
| ItemUpdating | Original value | Changed value | Original value |
| ItemUpdated | No value | No value | Changed value |
| ItemUpdated – sync | No value | No value | Original value |
| ItemDeleting | No value | No value | Original value |
| ItemDeleted | No value | No value | Null |
| ItemDeleted – sync | No value | No value | Null |
No value –> column value in the hash table was not available.
New value –> the new value for the column was available.
Changed value –> the updated value was available.
Original value—> the original value was available.
Null –> the item is not available.
As you can see, in the Post Synchronous ItemUpdated event attached to a library ( not a list), the properties.ListItem[“AField”] returns the original value (the value of a field before the update occurs) and there is no way to get the updated value. I’m not sure if this is a bug or by design, I’ll check and get back to you very soon.
Ayman El-Hattab's Technology Blog 