Using Generic Classes as Type Parameters

[Levi]

class A<Ta>
{
public A() { }
}

class B<TA, Ta>
where TA : A<Ta>
{
public B() { }
}

class Program
{
static void Main(string[] args)
{
B<A<int>, int> var = new B<A<int>, int>();

//how I'd like to do it
//B<A<int> > = new B<A<int> >();
}
}

Is there some combination of syntax that'll let me declare a variable
of type B as I'd like to do it? It's a bit clunky having to say that I
want int twice.

 

[Nicholas Paldino [.NET/C# MVP]]

Levi,

No, there is not a way to do it. You will have to declare it like that
on the type level every time. Type parameters on the method level can be
implied, but at the type level (except when indicating the type in static
methods), they can not be.

Hope this helps.

 

[Nicholas Paldino [.NET/C# MVP]]

Levi,

One other thing, you can always declare a type alias with the using
statement, and then use that. At the top of your file, you can do:

using MyGenericB = B<A<int>, int>;

Then, in your code, you can do:

MyGenericB var = new MyGenericB();

And it will compile fine.

 

[James Curran]

I don't have the ability to test this here, but this should work:

B <A<Ta>, Ta> CreateB<Ta>()
{
return new B<A<Ta>, Ta>()
}

static void Main(string[] args)
{
B<A<int>, int> var = CreateB<int>();
}


--
Truth,
James Curran
[erstwhile VC++ MVP]

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