Are templates usefull?

[luke]

Are they?
I mean, you could always downcast them for particular use, but then the
system would be well designed with intefaces instead of generics, and for
other uses I don't see any sense (collections excluded). Why do I need to
hold something of type 'object'? For what concrete usage? I am confused with
interfaces and generics... Please someone explain to me.

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

Re: Are templates usefull?

luke,

Generics are a great way to get general functionality while exposing
specific types.

You have already mentioned the example of collections, for example.

With interfaces and generics, they are a way of specifying the specific
type to use for the contract that makes up the interface.

For example, you know that the IEnumerator interface is going to iterate
through a list/collection/whatever. In order to support all types, it just
returns an object, which you then have to cast. This isn't type safe, and
an erroneous cast will be caught at run-time, not compile time.

With IEnumerator<T>, you don't have to cast, because the Current
property returns T. If you try to misassign this to another variable, you
catch it at compile time.

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard. caspershouse.co m

"luke" <luke@hotmail.c om> wrote in message
news:dr8f2h$4v3 $1@sunce.iskon. hr...[color=blue]
> Are they?
> I mean, you could always downcast them for particular use, but then the
> system would be well designed with intefaces instead of generics, and for
> other uses I don't see any sense (collections excluded). Why do I need to
> hold something of type 'object'? For what concrete usage? I am confused
> with interfaces and generics... Please someone explain to me.
>
>[/color]

[luke]

Re: Are templates usefull?

> With IEnumerator<T>, you don't have to cast, because the Current[color=blue]
> property returns T. If you try to misassign this to another variable, you
> catch it at compile time.
>
> Hope this helps.
>[/color]

Yes it does, thanks.

[Nick Hounsome]

Re: Are templates usefull?


"luke" <luke@hotmail.c om> wrote in message
news:dr8nlf$n27 $1@sunce.iskon. hr...[color=blue][color=green]
>> With IEnumerator<T>, you don't have to cast, because the Current
>> property returns T. If you try to misassign this to another variable,
>> you catch it at compile time.
>>
>> Hope this helps.
>>[/color]
>
> Yes it does, thanks.
>[/color]

But be aware that you can't just update all your old code because of at
least 1 big gotcha [it got me :-(] IList<T> does NOT derive from IList (and
there IS a good(ish) reason for this)

This causes a problem where a method must continues to take IList and you
are now trying to pass IList<T>