Currently am developing an item adding event in event receiver for a custom list. The list is updated using datasheet view, usually by adding bulk items (ex : 50 items ) to list using datasheet view.
I found that while my event receiver is not triggered for few items, the same event receiver works fine when adding single item to list each time.
I think that bulk updates causes issues in event receiver, anybody knows this issue?
When you are adding an item it updates the list item only once. But if you are using the ItemAdded there is another update happen on each list item in order to complete the whole operation. From performance perspective it is bad, but it is safe. Mean I also have seen this. Might be your environment has many event receivers. Try debugging and ensure every event receiver is bound to only 1 list or only the needed. This is something many people fail.
When adding multiple items in SharePoint list then ItemAdded event works better than ItemAdding event. ItemAdding event has never worked for me for bulk uploads but yes ItemAdded event always works good.
Hope this helps.
