Scott on Writing

# re: Friday Quiz: Question on .NET 2.0 Generics 8/20/2004 9:59 AM Rob Chartier

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnvs05/html/csharp_generics.asp


public class LinkedList<K,T> where K : IComparable<K>
{...}

There was also a best practices document that was pumped onto someone's blog (MS Employee), I belive on weblogs.asp.net, which explained why what you are trying to do is not usually considered a good idea. Something about keeping the interface for your API simple and easy to understand.

# re: Friday Quiz: Question on .NET 2.0 Generics 8/23/2004 6:18 AM Rodrigo Jordao

In order to create an instance of

class SuperFoo<S> where S : Foo<X>

you should be able to specify X in the creation expression:

SuperFoo<Foo<int>> sf = new SuperFoo<Foo<int>>();

but you can't, so the compiler can't know X unless the class declaration also has X, as in the LinkedList example. You should write:

class SuperFoo<S, X> where S : Foo<X>

now you can write:

SuperFoo<Foo<int>, int> sf = new SuperFoo<Foo<int>, int>();

or if you have a class like this:

class DerivedFoo<T> : Foo<T>

you can write:

SuperFoo<DerivedFoo<int>, int> sf = new SuperFoo<DerivedFoo<int>, int>();

and the constraint will be satisfied....

This is from the spec:

"In either case (class or interface constraint), the constraint may involve any of the type parameters of the associated type or method declaration as part of a constructed type, and may involve the type being declared, but the constraint may not be a type parameter alone."

# re: Friday Quiz: Question on .NET 2.0 Generics 8/23/2004 6:33 AM Rodrigo Jordao

And hey, you could try something like this too:

public class SuperFoo<T> {}

public class NewSuperFoo<T> : SuperFoo<Foo<T>> {}

# re: Friday Quiz: Question on .NET 2.0 Generics 8/24/2004 1:12 PM johnny

Just curious, can you give an example of what type of project would you use something like this?

Johnny