Question

I use this method called SearchConsequences to iterate through List<ValuesEO> of objects and perform some tasks, for getting values of particular fields, according to applied rules. I want to somehow simplify this code.

I want to switch (replace) everywhere in code the expression ValuesEO[i].powerR for other ValuesEO[i].otherField in the whole block of code.

At this time I do this just by block coping and changing it manually. So lets say, at the end, I have 5 blocks of really similar code blocks in this method. The only difference is in ValuesEO[i].otherField than ValuesEO[i].otherField2 ValuesEO[i].otherField3 … and so on.

I don’t like that block coping.

public Dictionary<Consequence,Cause> SearchConsequences(List<ResultsCatcher> smallTable, int n, ConnectHYSYS obj, int keyP, int keyR)//for one stream for one parameter
    {
        double threshold = 0.005;

        Dictionary<Consequence,Cause> collection = new Dictionary<Consequence,Cause>();

        //search in ValesE for each energy stream, for powerR
        for (int i = 0; i < smallTable[n].ValuesE.Count; i++)
        {
            //sort the smallTable
            smallTable.Sort((x, y) => x.ValuesE[i].powerR.CompareTo(y.ValuesE[i].powerR));

            //get the index of first occurrence of powerR >= threshold, if there is nothing bigger than threshold, index is null
            var tagged = smallTable.Select((item, ii) => new { Item = item, Index = (int?)ii });
            int? index = (from pair in tagged
                          where pair.Item.ValuesE[i].powerR >= threshold
                          select pair.Index).FirstOrDefault();

            //get needed information
            if (index != null)
            {
                int id = Convert.ToInt16(index);

                double newValue = smallTable[id].ValuesE[i].power;
                double newValueR = smallTable[id].ValuesE[i].powerR;
                TypeOfValue kindOf = TypeOfValue.power;
                Consequence oneConsequence = new Consequence(obj.EnergyStreamsList[i], newValue, newValueR, kindOf);

                Cause oneCause = new Cause();
                oneCause.GetTableHeader(smallTable[id]);

                collection.Add(oneConsequence,oneCause);
            }
        }
    }

Maybe it is easy to accomplish that and somewhere this problem is discussed.
But I really even don’t know how to google it.

Answer 1

This is a ready made program for you that demonstrates how to move your criteria/property selection outside your examination function. Have a look to see how fields criterias are matched.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Management;

namespace Test
{
    class Program
    {
        public class PowerValues
        {
            public double power;
            public double powerR;
            public double lightbulbs;
            public double lightbulbsR;
        }

        public static void DoSomething(IEnumerable<PowerValues> powerValues, Func<PowerValues, double> criteria, double treshhold)
        {
            var flaggedElements = powerValues.Where(e => criteria(e) > treshhold);
            foreach (var flagged in flaggedElements)
            {
                Console.WriteLine("Value flagged: {0}", criteria(flagged));
            }
        }

        public static void Main(string[] args)
        {
            List<PowerValues> powerValues = new List<PowerValues>();

            powerValues.Add(new PowerValues(){power=10, powerR=0.002, lightbulbs = 2, lightbulbsR = 2.006});
            powerValues.Add(new PowerValues(){power=5, powerR=0.004, lightbulbs = 4, lightbulbsR = 2.09});
            powerValues.Add(new PowerValues(){power=6, powerR=0.003, lightbulbs = 3, lightbulbsR = 2.016});

            Console.WriteLine("Power matching criteria . . . ");
            DoSomething(powerValues, (e) => e.powerR, 0.003);
            Console.WriteLine("Lightbulbs matching criteria . . . ");
            DoSomething(powerValues, (e) => e.lightbulbs, 3);

            Console.Write("Press any key to continue . . . ");
            Console.ReadKey(true);
        }
    }
}