I have my code working like this now:

  Protected Sub dsOTS_PerformSelect(ByVal sender As Object, ByVal e As SD.LLBLGen.Pro.ORMSupportClasses.PerformSelectEventArgs) Handles dsOTS.PerformSelect
    e.ContainedCollection.GetMulti(e.Filter, e.MaxNumberOfItemsToReturn, e.Sorter, e.Relations, e.PageNumber, e.PageSize)
  End Sub

But I'd like to do something like this so I can manipulate some of the collection fields first:

  Protected Sub dsOTS_PerformSelect(ByVal sender As Object, ByVal e As SD.LLBLGen.Pro.ORMSupportClasses.PerformSelectEventArgs) Handles dsOTS.PerformSelect
    e.ContainedCollection = OrderTrackingManager.DelvieryView(mydate)
  End Sub

How would I go about doing this?

Please try something like

yourLLBLGenProDataSource.EntityCollection = OrderTrackingManager.DelvieryView(mydate)