title: Store a custom value in a EKEvent (iPhone Calendar)
body: <p>My app integrates with the device calendar.  When a new item is added to my app we create a calendar entry for this item.  If the item is edited we need to update the calendar item.</p>
  
  <p>What I do now is put a GUID in the EKEvent.Notes but obviously this is visible to the user so we add a text "do not delete".  We then search the calendar for Notes containing the GUID to find the related item.</p>
  
  <p>What would be ideal is if the EKEvent had a Tag property or if there was some type of hidden field that could take a string value.  We could then store our related unique ID in this field and not clutter the user's notes field.</p>
  
  <p>Any suggestions on how to handle this?</p>
  
  <p>Thank you.</p>