C#•16mo ago

❔ Pass variable type as class parameter

Hey, so basically I have a class

class Number
{
  public string Type;
  public string Value;

  public Number(string type, string value)
  {
    Type = type;
    Value = value;
  }
}

class Number
{
  public string Type;
  public string Value;

  public Number(string type, string value)
  {
    Type = type;
    Value = value;
  }
}

What I want to do is if I do this for example

var num = new Number("long", "10000");

var num = new Number("long", "10000");

Number.Type shouldnt be string but rather a long; and Number.Value should contain the value

20 Replies

Theos•16mo ago

Later I want to add a simple check to see if value fits the type so for example 100000000 would be too big for a short etc

Angius•16mo ago

Do you want generics, perchance?

Theos•16mo ago

i think so, but I'm not exactly sure how to use them in my case

Angius•16mo ago

IParsable And .TryParse()

public bool Check<T>(string val) where T : IParsable<T>
{
    return T.TryParse(val, out var _);
}

public bool Check<T>(string val) where T : IParsable<T>
{
    return T.TryParse(val, out var _);
}

Something like that

Theos•16mo ago

what about public string Type;? Cuz for now its a string I cant just make it a public T Type

Angius•16mo ago

So you actually want the type to be a string?

Theos•16mo ago

when i create a class i pass a type as a string but in the class I want to store the actual type no a string

Angius•16mo ago

Why would you pass it as a string though...?

Theos•16mo ago

cuz i'm reading it from a txt file

Angius•16mo ago

Uh Well, maybe you can do some reflections tomfuckery to get an actual type from just it's string name

Theos•16mo ago

well, there is 3 possbile options in my case it can either be a short, long, int so maybe a simple switch?

Angius•16mo ago

I'd say so, yeah A switch expression even

Theos•16mo ago

but then public [what here?] Type;

Angius•16mo ago

You want the string type to be passed in the constructor? If so, I'd use a factory method instead

public MyClass<T>
{
    public T Value { get; set; }
    private MyClass<T>(){}

    public static GetInstance(string type)
    {
        return type switch {
            "int" => new MyClass<int>(),
            "long" => new MyClass<long>(),
            "short" => new MyClass<short>(),
            _ => throw new Exception("Unsupported type")
        };
    }
}

public MyClass<T>
{
    public T Value { get; set; }
    private MyClass<T>(){}

    public static GetInstance(string type)
    {
        return type switch {
            "int" => new MyClass<int>(),
            "long" => new MyClass<long>(),
            "short" => new MyClass<short>(),
            _ => throw new Exception("Unsupported type")
        };
    }
}

Something like this You wouldn't need to store a type even

Theos•16mo ago

alright, I'll get back to it tomorrow and see how it goes thanks

Thinker•16mo ago

(that should probably be in a static class? otherwise you'd have to call it using MyClass<int>.GetInstance("long"))

Angius•16mo ago

Huh, true So it'd need two classes

Thinker•16mo ago

Also what's the return type

Angius•16mo ago

Right

Accord•16mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Pass variable type as class parameter