Cast Exception Handler

//this is the code in the booking form
// time is public static
time = TimeSpan.Parse(dtpTime.Value.ToShortTimeString());
//this is the code in another form
while (rdr.Read())
{
    for (int i = 0; i < rdr.FieldCount; i++)
    {
        if ((TimeSpan)rdr[6] > Booking.time)
        {
            // etc etc
        }
    }
}