 <p>Wasn't sure what you meant by a 'dropdownList'. For this example I used a ComboBox.</p> <pre><code> Dim StartTime As DateTime = #12:00:00 AM# 'load combo box Do StartTimeDDL.Items.Add(StartTime.ToString("hh:mm tt")) StartTime = StartTime.AddMinutes(30) Loop While StartTime.TimeOfDay.TotalDays &gt; 0 Dim selectTime As DateTime = #2:10:12 PM# 'TEST find this &lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt; 'round time to 30 minutes Dim numSecs As Integer = (CInt(selectTime.TimeOfDay.TotalSeconds) \ 1800) * 1800 'the OP said 'les say current time is 12:00:00 AM than I was to select 12:30 AM" 'so.... numSecs += 1800 'round up 30 minutes ???????? 'create 'find' Dim ts As New TimeSpan(0, 0, numSecs) Dim findDate As New DateTime(ts.Ticks) StartTimeDDL.SelectedIndex = StartTimeDDL.FindStringExact(findDate.ToString("hh:mm tt")) </code></pre>