RecurrenceId Attribute of the CustomAction Element

During my session at SharePoint Saturday Boston – I mentioned that I would look into just what exactly RecurrenceId does, and make a post about it here. RecurrenceId is a token that is available for the URLAction element within the CustomAction element.

I did some additional research, and was able to find this via MSDN:

“A recurrence identifier that identifies a specific instance of a recurring appointment. It is used with the to uniquely identify the instance.”

The above quote is from an Exchange related article, however, it still fits the bill, and gives a little more useful information than the one found in the RecurrenceId Property link below, which is:

Returns the identifier (ID) of an instance of a recurrent item.

Paul Grenier (AutoSponge) who was attending my session, was spot on with his guess. The RecurrenceId property would be useful in the URLAction element to specifically identify a recurring event list item, and to only act on that specific item, as recurring events within events lists are just one single list item, and not copies of the original with their own specific GUIDs. They have the same GUID as the original event, however, just have an incremented RecurrenceId that can be used to directly identify that specific occurrence of the event.

More information on this SPListItem Property can be found here in the WSS 3.0 SDK: SPListItem.RecurrenceID Property (Microsoft.SharePoint), however, there is not much there.

As of my session on Saturday, I had never needed to use this attribute before in my travels, and virtually the only documentation on it I could find before SharePoint Saturday Boston, was that you cannot use it with the Edit Control Block. This doesn’t make much sense to me however, why it is even available, as I would think the only time this would be useful, is to directly interact with an event list item from the Edit Control Block.

Anyhow – there is now a blog posting out in the wild for others to consume regarding the RecurrenceId attribute. I hope this helps someone else out.