> I'm having a problem that I'm quite sure is quite simple
> to solve but for some reason I just can get it to work.
>
> All I want to do is to create an interface such as the following:
>
> --------------------------------------------------------------
> ----------
> -----------------------------
>
> using System;
> using System.Collections.Generic;
> using System.Text;
>
> public interface IDataManager
> {
> List<T> SelectData();
> int UpdateData(<T> objectToBeUpdated);
> bool InsertData(<T> objectToBeInserted);
> bool DeleteData(<T> objectToBeDeleted);
> }
>
> --------------------------------------------------------------
> ----------
> -----------------------------
Either do:
public interface IDataManager<T>
where T:..
{
List<T> SelectData();
int UpdateData(T objectToBeUpdated);
bool InsertData(T objectToBeInserted);
bool DeleteData(T objectToBeDeleted);
}
or do:
public interface IDataManager
{
List<T> SelectData<T>();
int UpdateData<T>(T objectToBeUpdated);
bool InsertData<T>(T objectToBeInserted);
bool DeleteData<T>(T objectToBeDeleted);
}
Though, if I were you, I'd stay away from generics in interfaces, or at
most use the second option. The reason for this is
that an interface can be implemented by multiple types, and if your code has to
work with the interface, the type of 'T' is often
unknown, so option 1 has a problem: at some point, T has to be declared
somewhere.
Interfaces offer you a different way of generic programming, if you mix
that with generics, you mitigate the generic program
ability of interfaces and at the same time make your code more complex than it
should be.
Frans
>
> According to all the documentation I've read, this shouldn't
> be a problem, but every time I try to compile, the following
> compile error is thrown:
>
> Error 1 The type or namespace name 'T' could not be found (are
> you missing a using directive or an assembly reference?)
>
>
> This is probably blatantly obvious for most of you but I just
> haven't find a way to solve the problem.
>
> I am assuming I have to tell the compiler that T will be a
> generic type but I haven't found a way of doing it and as all
> the documentation and examples I've seen don't mentione it,
> it makes me think it's something very obvious...(not for me though).
> What is it that I am missing?
>
> Is there a secret reference I should be adding?
> Maybe a secret using statement that I am missing?
>
>
> Any ideas?
>
>
> Thanks in advance,
> Yago Alvarado
>
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