feeding a dynamic interpolation function to a series

DataSeries.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Numerical
{
    public class DataSeries
    {
        public List<double> X { get; set; }
        public List<double> Y { get; set; }
        public Func<double, double, double, double, double, double> Interpolator { get; set; }

        public int Length
        {
            get { return X.Count; }
        }

        public double XMax
        {
            get { return X[Length - 1]; }
        }
        public double XMin
        {
            get { return X[0]; }
        }

        public DataSeries()
        {
            X = new List<double>();
            Y = new List<double>();
            Interpolator = StandardInterpolator;
        }


        public void Add(double x, double y)
        {
            if (X.Count == 0 || x > XMax)
            {
                // No previous items in the list or the current x is larger than
                // what is already in the list
                X.Add(x);
                Y.Add(y);
            }
            else
            {
                // Instead of adding to the end, the current x needs to be inserted
                // at an intermediate row to keep a sequential X.
                for (int rowIndex = 0; rowIndex < Length; rowIndex++)
                {
                    if (x < X[rowIndex])
                    {
                        X.Insert(rowIndex, x);
                        Y.Insert(rowIndex, y);
                        break;
                    }
                }
            }
        }
        public double GetValue(double x)
        {
            if (x < XMin || x > XMax) return 0;

            int i = 0;
            var searchResult = Array.BinarySearch(X.ToArray(), x);

            if(searchResult < 0)
            {
                i = ~searchResult - 1;
                return Interpolator(X[i], X[i + 1], Y[i], Y[i + 1], x);
            }
            else
            {
                return Y[i];
            }
        }

        public double StandardInterpolator(double x1, double x2, double y1, double y2, double value)
        {
            double A = (x2 - value) / (x2 - x1);
            double B = 1 - A;
            return A * y1 + B * y2;
        }
    }
}