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Accepted
Iván Rodríguez
Asked: 2022-01-19 06:42:33 +0800 CST 2022-01-19 06:42:33 +0800 CST

Is it possible to add cases to a switch dynamically (at runtime)? C#

  • 772

I am wondering if it is possible to add cases to a switch at runtime. That is, start with an empty switch like the following:

switch (opcion)
        {
            default:
                 break;
        }

And then add cases if necessary

switch (opcion)
        {
            case Case1:
                {
                  break;
                }

                .....
                .....
                .....
            case CaseN:
                {

                    break;
                }
            default:
                 break;
        }

Say that I have made a code that "emulates" (more or less) what I want to do and it is the following:

//--------------------------------------------------------------
public class DinamicSwith<T> where T : IComparable
{
    public delegate T Delegate();
    public List<Delegate> caseList;
    public List<T> option;
    public Delegate Default;
    T defaultReturn;
    bool isDefaultSet;

    public DinamicSwith(T defaultReturn)
    {
        caseList = new List<Delegate>();
        option = new List < T >();
        this.defaultReturn = defaultReturn;
    }
    public void AddCase(Delegate func, T option)
    {        
        caseList.Add(func);
        this.option.Add(option);
    }
    public void AddDefault(Delegate func)
    {
        Default = func;
        isDefaultSet = true;
    }
    public T Execute(T option)
    {
        for (int i = 0; i < caseList.Count; i++)
        {
            if (this.option[i].CompareTo(option)==0)
            {
                return caseList[i]();
            }
        }

        if(isDefaultSet)    
            Default();

        return defaultReturn;
    }
}
//--------------------------------------------------------------

What I want to know is if there is any way to do it "by default"... that is, a method that provides you with the C# language itself (a simpler and more efficient way). Thank you!!

c#

1 Answers

  1. Best Answer

    Actually what you are doing is a map , in pseudo code it would be something like this:

    Map<Case, Function> switch = ...
Function fun;
if (switch.hasKey(myCase)) {
    fun = switch.get(MyCase);

} else {
    fun = switch.get(DEFAULT);
}
fun(...);

    At any time you could add new "cases", associated with a new function. This could be done in any programming language. And really, the switches are usually transformed when compiling to a hash table so as not to have to compare case by case and that any input is resolved in O(1), no matter how many cases there are (your implementation goes through all of them until it finds the one that is meets).

    • 10