It is rather simple. The true of that provider page can actually be found in the server control's library. It is all about inheritance. It is the same as having the following code:
public class A : CollectionBase {}
public class B : A {}
In effect, what they have done is have the following code in their library:
public abstract class SomePage : Page {
// class A in the above example
}
However, an ASP.NET page by itself is a class! It is converted into a class at runtime by the parser. So the page will be named "ServingPage" and therefore (by "default"), it should look like this:
public class ServingPage_aspx : Page {
// nothing yet
}
But what that <%@ Page %> declarative does is tells that the class will not inherit from the Page class. Instead, it will compile from the specified class. Therefore, it will rather create code like so:
public class ServingPage_aspx : SomePage {
// serves as class B in first example
}
And that page does not contain "just one line of code". In fact, all its code is truely found in the class it is inheritting from.
-- Justin Lovell