For example, you can hook into the Item Updating event for a document library and prevent a user from changing a certain column.
The code might look like this: When they say “not available for post events on list items”, do they mean after events (like Item Updated, Item Deleted, etc)?
If you wish to modify a property value on the list item during the event, the value should be updated in After Properties property of the properties parameter.
Share Point reads these values from the event parameter and modifies the item accordingly when the actual operation runs (e.g.
That means that if you register a event receiver Item Adding to your list, every time you add new item to your list, that event will trigger, and custom code that you put in your Event Receiver will be executed.