How to return the name of an instance of a class?

Question

To avoid having to manually type the data after an update to the objects, I decided to create a method of type static to be accessed by passing the object as parameter.

    public static void Relatorio(Trem trem)
    { 

        Console.WriteLine($"{trem} - PESO ATUAL:       {trem.getPesoVagao()}");
        Console.WriteLine($"{trem} - PESO SUPORTADO:   {trem.getCargaMAX()}");
        Console.WriteLine($"{trem} - CARGA DISPONÍVEL: {trem.CargaRestante()}");

        Console.WriteLine();
        Console.WriteLine();
    }

That would keep me from writing the report on Main() whenever you make a change to the object, but the returned name that should be "T2" is returning as SobrecargaDeMetodos.Trem.

I call the method as follows by passing the object to be analyzed as parameter. The part showing the result works perfectly, but the name does not.

Trem.Relatorio(T2);

Answer 1

This is a misconception. First there is no instance name, there is variable name. It may even be that in this case a name is equal to the variable name, but it cannot always represent any name in a variable name. But there is also a misunderstanding of what is a variable. Variables are local and they don’t go from one context to another, so what you want doesn’t make sense, actually what you’re printing isn’t even what you’re imagining. The solution to this very simple:

public static void Relatorio(Trem trem, string nome) {
    WriteLine($"{nome} - PESO ATUAL:       {trem.getPesoVagao()}");

There it calls:

Trem.Relatorio(T2, "T2");

or if you think you can change that name (which seems to me something strange, but anyway, I will not discuss other possible mistakes of this design), can even use:

Trem.Relatorio(T2, nameof(T2));

I put in the Github for future reference.

This only ensures that if the variable name is changed it gives a build error in the passage of the string, so make you change your name there too.

Maybe there are other misconceptions in this.

Answer 2

Another option is to add a property Nome to your class Trem. That way all the trains would have a Nome

public class Trem{
    public string Nome{get; set;}
    //...
}

And every time you create a Voce train you name it. var t = new Trem(){Nome = "t2"};. And in your report you would use your property:

Console.WriteLine($"{trem.Nome} - PESO ATUAL:       {trem.getPesoVagao()}");
//...