Private Enum WeekOfMonth As Integer
   First = 1
   Second = 2
   Third = 3
   Fourth = 4
   Last = 5
End Enum

Private Sub ShowStartAndEndDates()
   ' Get all time zones from system
   Dim timeZones As ReadOnlyCollection(Of TimeZoneInfo) = TimeZoneInfo.GetSystemTimeZones()
   ' Get each time zone
   For Each timeZone As TimeZoneInfo In timeZones
      Dim adjustments() As TimeZoneInfo.AdjustmentRule = timeZone.GetAdjustmentRules()
      ' Display message for time zones with no adjustments
      If adjustments.Length = 0 Then
         Console.WriteLine("{0} has no adjustment rules", timeZone.StandardName)
      Else
         ' Handle time zones with 1 or 2+ adjustments differently
         Dim showCount As Boolean = False
         Dim ctr As Integer = 0
         Dim spacer As String = ""
         
         Console.WriteLine("{0} Adjustment rules", timeZone.StandardName)
         If adjustments.Length > 1 Then showCount = True : spacer = "   "  
         ' Iterate adjustment rules
         For Each adjustment As TimeZoneInfo.AdjustmentRule in adjustments
            If showCount Then 
               Console.WriteLine("   Adjustment rule #{0}", ctr+1)
               ctr += 1
            End If
            ' Display general adjustment information
            Console.WriteLine("{0}   Start Date: {1:D}", spacer, adjustment.DateStart)
            Console.WriteLine("{0}   End Date: {1:D}", spacer, adjustment.DateEnd)
            Console.WriteLine("{0}   Time Change: {1}:{2:00} hours", spacer, _
                              adjustment.DaylightDelta.Hours, adjustment.DaylightDelta.Minutes)
            ' Get transition start information
            Dim transitionStart As TimeZoneInfo.TransitionTime = adjustment.DaylightTransitionStart
            Console.Write("{0}   Annual Start: ", spacer)
            If transitionStart.IsFixedDateRule Then
               Console.WriteLine("On {0} {1} at {2:t}", _
                                 MonthName(transitionStart.Month), _
                                 transitionStart.Day, _
                                 transitionStart.TimeOfDay)
            Else
               Console.WriteLine("The {0} {1} of {2} at {3:t}", _
                                 CType(transitionStart.Week, WeekOfMonth).ToString(), _
                                 transitionStart.DayOfWeek.ToString(), _
                                 MonthName(transitionStart.Month), _
                                 transitionStart.TimeOfDay)
            End If
            ' Get transition end information
            Dim transitionEnd As TimeZoneInfo.TransitionTime = adjustment.DaylightTransitionEnd
                              
            Console.Write("{0}   Annual End: ", spacer)
            If transitionEnd.IsFixedDateRule Then
               Console.WriteLine("On {0} {1} at {2:t}", _
                                 MonthName(transitionEnd.Month), _
                                 transitionEnd.Day, _
                                 transitionEnd.TimeOfDay)
            Else
               Console.WriteLine("The {0} {1} of {2} at {3:t}", _
                                 CType(transitionEnd.Week, WeekOfMonth).ToString(), _
                                 transitionEnd.DayOfWeek.ToString(), _
                                 MonthName(transitionEnd.Month), _
                                 transitionEnd.TimeOfDay)
            End If
         Next
      End If   
      Console.WriteLine()
   Next 
End Sub