hi,
Check this.
DateTime dt1 = Convert.ToDateTime("2013-10-04 09:00:00");
DateTime dt2 = Convert.ToDateTime("2013-10-04 18:00:00");
TimeSpan dt;
if (dt1 > dt2)
{
dt = dt1 - dt2;
}
else
{
dt = dt2 - dt1;
}
double minutes = dt.TotalMinutes;
double total15min = minutes / 15;
Hope it helps you.
Thanks