The code in this post will show how to create recursive calendar events. The data about the Recurrence is stored in a field named "RecurrenceData". It is xml based data. One of the easy ways to determine what the value of "RecurrenceData" should be, is to create a recurrence item in the list from UI, get that item from code and find the data. Example:
There are few other fields which need to be updated when creating a Recurrence event apart from "RecurrenceData". "EventType" which needs to be set to 1,"UID" which takes a GUID and "Recurrence" which is set to true. Here is a sample code which creates a Recurrence event.
Here is sample recurrence xml data
This is how it shows in UI. It is a weekly recurrence:
Here is the Recurrence event in the UI created as a result of above code: