private void UpdateDateRange()
 {
     DateConverter dc = new DateConverter();
     String nextDate = (String)dc.Convert(dateNext.Value, typeof(String), ":sd", null);
     DateTime pastVal;
     switch (lstFrequency.SelectedIndex)
     {
         case 0:
             pastVal = dateNext.Value.Value.AddDays(-6);
             break;
         case 1:
             pastVal = dateNext.Value.Value.AddDays(-13);
             break;
         case 2:
             pastVal = dateNext.Value.Value.AddMonths(-1).AddDays(1);
             break;
         default:
             pastVal = dateNext.Value.Value;
             break;
     }
     String pastDate = (String)dc.Convert(pastVal, typeof(String), ":sd", null);
     lblRecursiveDayClarifier.Text = String.Format("i.e. the next summary will be for all shifts between {0} and {1} inclusive.", pastDate, nextDate);
 }