private static double GetNextSlope(int index, int count, List <DateValue> values, DateValue dv)
{
double nextSlope = 0;
if (index < count - 1)
{
DateValue dv2 = values[index + 1];
nextSlope = (dv2.Value - dv.Value) / (dv2.Date.ToOADate() - dv.Date.ToOADate());
}
return(nextSlope);
}