OTHER GENERIC TYPES
In addition to methods and classes, structs, delegates, and interfaces can also have type parameters. Structs and interfaces are obvious; the syntax looks much like that of classes:
public struct MyPoint<T> where T : struct {
public MyPoint(T x, T y) {
this.x = x;
this.y = y;
}
private readonly T x;
public T X {
get { return x; }
}
private readonly T y;
public T Y {
get { return y; }
}
}
public interface IListItem<T> {
T Value { get; }
ListItem<T> Prepend(T value);
}
Even with delegates there’s nothing surprising about the syntax. Following is an example of an alternative Factory implementation called ParameterFactory that uses a creation delegate instead of relying on the new() constraint and using a default constructor:
public delegate R CreateDelegate<T, R>(T param);
public class ParameterFactory<T, R> {
CreateDelegate<T, R> createDelegate;
public ParameterFactory(CreateDelegate<T, R> createDelegate) {
this.createDelegate = createDelegate;
}
// ...
}
This includes the declaration of the CreateDelegate, which represents a function that takes a parameter of type T and returns a value of type R.
This is a good example of a statement that was made in Chapter 3, where the standard delegate types Func<...> were introduced. The ParameterFactory works with its own delegate type CreateDelegate instead of ...
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