populate the dropdown list with time interval in C#

private void populateDropdown(ComboBox dropdown, DateTime startTime, DateTime endTime, TimeSpan interval)
{
    dropdown.Items.Clear();

    DateTime time = startTime;

    while (time <= endTime)
    {
        dropdown.Items.Add(time.ToString("HH:mm tt"));
        time = time.Add(interval);
    }
}

populateDropdown(comboBox1, new DateTime(2000, 1, 1, 8, 0, 0), new DateTime(2000, 1, 1, 12, 30, 0), new TimeSpan(0, 30, 0));

DateTime start = DateTime.ParseExact(txtStart.Text,"HH:mm tt", null);
       DateTime end = DateTime.ParseExact(txtEnd.Text, "HH:mm tt", null);

       int interval = 30;
       List<string> lstTimeIntervals = new List<string>();
       for (DateTime i = start; i < end; i =i.AddMinutes(interval))
           lstTimeIntervals.Add(i.ToString("HH:mm tt"));

       dropdownList.DataSource = lstTimeIntervals;
       dropdownList.DataBind();

public List<string> GetTimeIntervals()
{
	List<string> timeIntervals = new List<string>();
	DateTime date = DateTime.MinValue.AddHours(6); 
	DateTime endDate = DateTime.MinValue.AddDays(1).AddHours(6); 
	while (date < endDate)
	{
		timeIntervals.Add(date.ToShortTimeString());
		date = date.AddMinutes(15);
	}
	return timeIntervals;
}</string>

JUST EXECUTE THIS SP IN SQL AND BIND YOUR dropdown list



ALTER PROC TIMELIST(@Stime NVARCHAR(20),@Etime NVARCHAR(20),@MINInterval INT )
AS
BEGIN

DECLARE @newtime NVARCHAR(20)
SET @newtime=@Stime
DECLARE @SRnO INT
SET @SRnO=1

DECLARE @TEM TABLE (ID INT ,TIMES NVARCHAR(20))

WHILE(CONVERT(TIME,@newtime)<=CONVERT(TIME,@Etime))
BEGIN
   INSERT INTO @TEM VALUES(@SRnO,CONVERT(varchar(15),CAST(@newtime AS TIME),100))
    SET @SRnO=@SRnO+1
	SET @newtime=dateadd(MINUTE, @MINInterval,CONVERT(TIME,@newtime) )
END

SELECT * FROM @TEM
END

--EXEC  TIMELIST '8:00AM','12:30PM',30 


ID	TIMES
1	8:00AM
2	8:30AM
3	9:00AM
4	9:30AM
5	10:00AM
6	10:30AM
7	11:00AM
8	11:30AM
9	12:00PM
10	12:30PM