C#•9mo ago

Update an enum in a child class

I have a class Gastanker that inherts from Olietanker, I need to update the Lading enum in Olietanker for Gastanker class, can someone help me with this?

34 Replies

TheUnquietOP•9mo ago

    public class Gastanker : Olietanker
    {
        public enum Lading
        {
            LPG,
            LNG,
            amoniak
        }

        public Gastanker(double lengte, double breedte, int tonnage, string naam, int aantalContainers, double volume, Lading lading) : base(lengte, breedte, tonnage, naam, aantalContainers, volume, lading)
        {
        }
    }
    public class Olietanker : Containerschip
    {
        public double Volume { get; set; }
        public Lading _lading { get; set; }
        public enum Lading
        {
            Olie,
            Benzeen,
            Desel,
            Nafta
        }
        public Olietanker(double lengte, double breedte, int tonnage, string naam, int aantalContainers, double volume, Lading lading) : base(lengte, breedte, tonnage, naam, aantalContainers)
        {
            Volume = volume;
            _lading = lading;
        }
    }

    public class Gastanker : Olietanker
    {
        public enum Lading
        {
            LPG,
            LNG,
            amoniak
        }

        public Gastanker(double lengte, double breedte, int tonnage, string naam, int aantalContainers, double volume, Lading lading) : base(lengte, breedte, tonnage, naam, aantalContainers, volume, lading)
        {
        }
    }
    public class Olietanker : Containerschip
    {
        public double Volume { get; set; }
        public Lading _lading { get; set; }
        public enum Lading
        {
            Olie,
            Benzeen,
            Desel,
            Nafta
        }
        public Olietanker(double lengte, double breedte, int tonnage, string naam, int aantalContainers, double volume, Lading lading) : base(lengte, breedte, tonnage, naam, aantalContainers)
        {
            Volume = volume;
            _lading = lading;
        }
    }

Keswiik•9mo ago

What do you mean by "update the Lading enum"?

TheUnquietOP•9mo ago

hey there, I have an enum Lading in the base class it has these items : Olie, Benzeen, Desel, Nafta while in the child class the Lading enum should contain LPG, LNG, amoniak

Keswiik•9mo ago

Enums do not change values depending on where they're used, and in .net enums are basically named int values (starting at 0 by default)

Omnissiah•9mo ago

yeah you should have another enum entirely

Keswiik•9mo ago

Or one enum that holds all of the allowed values

Omnissiah•9mo ago

meh at this point use a static interface or real classes

TheUnquietOP•9mo ago

makes sense, thing is the inheritance has to stay there and the child class can't use the enum values from the base class is there a way to perhaps, hide the enum from that child class? this is a school project all about inheritance

Omnissiah•9mo ago

iirc if the field/property is re-declared in a inherited class with a new modifier (and the new enum type) it should work

TheUnquietOP•9mo ago

right I thought so aswell, however this results in a conflict between types in the constructor Argument 7: cannot convert from 'BL.models.Gastanker.Lading' to 'BL.models.Olietanker.Lading'

Omnissiah•9mo ago

you can just pass a default value

TheUnquietOP•9mo ago

how so?

Omnissiah•9mo ago

field will not be used, so 🤷

TheUnquietOP•9mo ago

I don't understand what you mean by default value

Omnissiah•9mo ago

any value, from just (Lading)0 or the first one of the enum

TheUnquietOP•9mo ago

like this?

        public Gastanker(double lengte, double breedte, int tonnage, string naam, int aantalContainers, double volume, Lading lading = 0) : base(lengte, breedte, tonnage, naam, aantalContainers, volume, lading)
        {
        }

        public Gastanker(double lengte, double breedte, int tonnage, string naam, int aantalContainers, double volume, Lading lading = 0) : base(lengte, breedte, tonnage, naam, aantalContainers, volume, lading)
        {
        }

br4kejet•9mo ago

I would probably use a string to represent that value instead of an enum

TheUnquietOP•9mo ago

you think so?

br4kejet•9mo ago

Yeah, or merge all the values of the different Lading enums

TheUnquietOP•9mo ago

teacher just said it could be any of these values so I thought of enums

br4kejet•9mo ago

public enum Lading
{
  LPG,
  LNG,
  amoniak,
  Olie,
  Benzeen,
  Desel,
  Nafta
}

public enum Lading
{
  LPG,
  LNG,
  amoniak,
  Olie,
  Benzeen,
  Desel,
  Nafta
}

TheUnquietOP•9mo ago

sure, but how do I make sure that the base class only uses the last 4 and the child class the first 3

br4kejet•9mo ago

You could check the range in the constructors but that gets weird for the base class constructors I've never seen this type of enum usage where each derived class has its own publicly exposed set of enum properties. I would just use something like a string in this case

TheUnquietOP•9mo ago

there is really no way of ovveriding these enums I'll do that for now then, thank you all @br4kejet @dont @ded

br4kejet•9mo ago

Having your oil tanker class derived from the gas tanker class seems a bit odd though, would it not be better to make them both extend Containerschip?

TheUnquietOP•9mo ago

they both use volume tho while Containerschip doesn't

br4kejet•9mo ago

Or create a class between Containerschip and the oil/gas tanker classes that has those properties like lengths, voluime, etc. like BaseTanker

TheUnquietOP•9mo ago

intresting

br4kejet•9mo ago

Then the oil and gas tankers derive from that class, and then you could do what you're doing now where the oil and gas tankers have their own enum things

TheUnquietOP•9mo ago

and BaseTanker inherits from Containerschip?

br4kejet•9mo ago

Yeah

TheUnquietOP•9mo ago

alright I'll go for this one then, thanks man

br4kejet•9mo ago

The thing about OOP is sometimes you have to redefine the same properties for different classes because extending a base class isn't really possible, and if you ever run into that, you might have to use some sort of composition class that contains those properties that can be shared across different types. You might not run into it, but it's an annoying thing to deal with when using complicated inheritance 😛

Omnissiah•9mo ago

exactly, also the problem is that you can only inherit one concrete class

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Update an enum in a child class