CODEWITHSUNDEEP
c#.netgenerics
CoolStraw
CoolStraw

Reputation: 5390

C# Generics and types

I have a generic method something like:

public abstract T method<T>(int arg) where T : class, new();

Then I implement it in the child class

public MyType method<MyType>(int arg){
    MyType e = new MyType();

    e.doStuff (arg); // ERROR HERE

    return s;
}

But I can't access MyType's members... How come ? Is there something I can add to enable them or something ?

Thank you

Miloud

Upvotes: 4

Views: 432

Answers (2)

Albin Sunnanbo
Albin Sunnanbo

Reputation: 47038

You can do like this (note that I have moved some of your generic parameters and constraints around).

public class MyType
{
    public void doStuff(int i){}
}
public abstract class ABase<T>where T : class, new()
{
    public abstract T method(int arg);
}

public class AChild : ABase<MyType>
{
    override public MyType method(int arg)
    {
        MyType e = new MyType();

        e.doStuff(arg); // no more error here

        return e;
    }
}

Upvotes: 3

Marc Gravell
Marc Gravell

Reputation: 1062502

C# does not have template specialization. You nave simply declared a new method with the type-parameter named MyType, which has nothing to do with the class named MyType.

You can cast, or there are generic constraints you use to declare that T is at least a MyType.

Another option would be to make the base-type itself generic in T (and remove the generic from the method), and have the concrete type : TheBaseType<MyType>

Upvotes: 3

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