How to "mount" a multiple variable?

Question

Would it be possible to mount a variable to pass a value to it? For example:

var teste0 = "valor";
var teste1 = "outro valor";
var teste2 = "mais um valor";

for(int i=0;i<3;i++){
    teste+i = "mudou "+i;
}

Look at the teste+i. Even though I hoped it wouldn’t work, I tried it this way and I was wrong.

Is there any way I can assemble the variable as in the idea of the example?

Answer 1

Yes, it is possible, it is one of the most basic and known techniques of programming. You do this with a variable of type array. A array is a variable that stores variables and so you can access them in exactly the same way, only the slightly different syntax.

Do not use a dictionary for this, it is totally unnecessary, slow, unproductive and insecure, even less use more complex reflection or solutions that have the same problems sharply (ie the solutions of the other two answers). Look how simple, safe and performative:

using static System.Console;

public class Program {
    public static void Main() {
        var teste = new string[] {"valor", "outro valor", "mais um valor" };
        for (var i = 0; i < 3; i++) teste[i] = "mudou " + i;
        foreach(var item in teste) WriteLine(item );
    }
}

Behold working in the ideone. And in the .NET Fiddle. Also put on the Github for future reference.

Answer 2

I would recommend for this situation you use a string dictionary.

Dictionary<string, string> dictionary = new Dictionary<string, string>();
dictionary.Add("teste0", "valor");
dictionary.Add("teste1", "outro valor");
dictionary.Add("teste2", "mais um valor");

for(int i=0;i<3;i++) {
    Console.WriteLine(dictionary["teste" + i.ToString()]);
} 

Answer 3

It is not possible to do this, at least not in C#. However, you can use reflection for this, however, the variables will need to be public and static and outside the scope of void.

public class Program {

    // converta para propriedades
    public static string teste0 {get; set;} = "valor";
    public static string teste1 {get; set;} = "outro valor";
    public static string teste2 {get; set;} = "mais um valor";

    public static void Main(string[] args) {
        for(int i = 0; i < 3; i++) {
            string nomeVariavel = "teste" + i.ToString();
            string value = "Alguma Coisa";

            var propInfo = typeof(Program).GetProperty(nomeVariavel);
            if (propInfo != null)
            {
                propInfo.SetValue(propInfo, value, null);
            }
        }

        Console.WriteLine(teste0);
        Console.WriteLine(teste1);
        Console.WriteLine(teste2);
    }
}

If you find it more convenient, you can make a small method for it:

public static void AlterarValor(Type objTipo, string varName, object value) {
    var propInfo = objTipo.GetProperty(varName);
    if (propInfo != null)
    {
        propInfo.SetValue(propInfo, value, null);
    }
}

And wear it like this:

AlterarValor(typeof(Program), "teste0", "Olá, mundo!");