How can I loop in 2D grid decision tree in C#?

Question

I have a list of objects I must set a property based on two criteria the 2D grid looks like this:

Property 2\Property 1   B<80        80<B<100       100<B<120           B>120
A < 100                 None          Red           Orange            Orange
100 < A < 120           None          Red           Orange             Green
120 < A < 140           None          Red           Green              Green
140 < A                 None         Orange         Green              Green

Is there a good way to loop Property 1 and Property 2 to dynamically set the object property? It is a possibility that in the future we add few criteria and I guess that doing multiple ifs isn't a good solution. I'm trying to avoid redundant code.

Thanks

Answer 1

If we could convert the 2 conditions for A and B into a system with a scale of 0-3:
if A<100 -> Ascale = 0
else if A<120 -> Ascale = 1
etc. and for B:
if B<80 -> Bscale = 0
else if B<100 -> Bscale = 1
etc.

Then we could use a 2d array for looking up the correct output response:
out = arrayname[Ascale][Bscale];

But I don't think this saves anything over simply hard-coding it as ifs, when only the possibility of a few extra ones, I think that hard-coding is the best solution for this.

Answer 2

I would recommend using an array lookup if you suspect things will change frequently. It would be best to load the data from a database or external file (to make configuration easy), but here I have hard coded the arrays:

        int[] alimits = new int[] { 100, 120, 140, int.MaxValue };
        int[] blimits = new int[] { 80, 100, 120, int.MaxValue };
        int aval = 125;
        int bval = 110;

        int aindex = 0;
        for (int i = 0; i < alimits.Count(); i++)
            if (aval < alimits[i])
                aindex = i;

        int bindex = 0;
        for (int i = 0; i < blimits.Count(); i++)
            if (bval < blimits[i])
                bindex = i;

        string[,] values = new string[,] {
            {"None", "Red", "Orange", "Orange"}, 
            {"None", "Red", "Orange", "Green"},
            {"None", "Red", "Green", "Green"},
            {"None", "Orange", "Green", "Green"}};

This is untested, but should give you the basic idea. You get the result as values[aindex, bindex].

Answer 3

class AbstractSetter { void SetObjectProperty(); }

class SetterLessThen100 : AbstractSettter { /* Implement code for the A<100 case */}

Implement list of setter objects that acts over the object for every case available. Add all of them to the AbstractSetters collection, iterate over it and call SetProperty() abstract method( thow overload on every concrete object). And in the future if you have some other condition to add, it's enough to implement new Setter and add it to the AbstractSetters collection.

Sorry , I have not enough time to write all code, hope it's clear. Good luck.