This is what we have for lists: For both lists and libraries: No value means that column value in the hash table was not available.
New value means that the correct value for the column was available.
When dealing with event receivers in Share Point custom code, we use the Before Properties and After Properties to get a hash table of properties consisting of string/value pairs that correspond to fields in the SPItem object before and after the event occurred respectively.
Share Point has a built-in infrastructure that allows certain SP objects to raise events that can be handled by custom code.
Given the asynchronous nature of the Item Added, if you change the data content, you are not 100% sure that the form displayed to the user include the new data and thus avoid conflicts backup.
For this we must add the synchronization parameter to our xml definition.
If not, kudos to you for tackling the object model with reckless abandon.These events could be web events (Web Adding, Web Provisioned, Web Deleting etc), feature events (Feature Activated, Feature Deactivated etc) or most popularly, list item events (Item Updated, Item Updating, Item Added etc).Before Properties and After Properties are available for the different event receiver classes. With the exception of feature events, here is a full list of available Share Point events, event receivers, and event hosts for quick reference.Additional information that is important is that during the upload of a document by a user in a library, adding events are triggered after addition of the upload but before the user can fill in themetadata! If you plan to modify the contents of the properties of this document at the event”Item Added”, your users may see a message like this when they will safeguard their metadata: “File ‘mydoc.pdf’ has been modified by ‘user’ the ‘date'”.To avoid this error, we can define the event “Item Added” as synchronous!I should also point out that I know the difference between a metaphor and simile in case that was bothering you from the opening sentence.