<Extension()> _
Public Function TimeIntervals(ByVal DateNavigator As DateNavigator) As TimeIntervalCollection
    Dim dc As List(Of DateTime) = (From x In DateNavigator.Selection Order By CDate(x) Select CDate(x)).ToList
    TimeIntervals = New TimeIntervalCollection
    Dim startdt As DateTime = DateTime.MinValue, enddt As DateTime = DateTime.MinValue
    For Each dt As DateTime In dc
        If startdt = DateTime.MinValue Then startdt = dt
        If enddt > DateTime.MinValue _
        AndAlso enddt.AddDays(1) < dt Then
            TimeIntervals.Add(New TimeInterval(startdt, enddt.Subtract(startdt)))