Question

Okay, this is a bit abstract, but here goes:

I’m creating a website and I want to have a field, ‘foo’, that I can access from any page on the site. I figured the best way to do this would be to create a subclass of Page called ‘bar’, add the protected field ‘foo’ to it, and then have all my webpages inheret from ‘bar’. Ta-da. Every page now has foo.

But now I add controls to my pages, and I want them to have access to ‘foo’.

Well, now foo can’t be protected, so it’s public. Fine. But how do the controls know about ‘foo’? I can access foo by doing something like this in my control:

Foo foo = ((Bar)Page).foo; 

This works, but strikes me as a bit ugly. I’d really like to just be able to use foo. I figure, hey, maybe I can do the same trick with my controls that I did for page. I create a new class, ‘blargh’ that inherits from UserControl, and grab foo in there the ugly way. Then I have my controls inherit from blargh. Yay!

Except it doesn’t work. When I start up the project it complains about the line trying to access ((Bar)Page).foo, because Page is null. Why? How could Page be null? When I look at the call stack I get no help.

Is there an easy, well understood way to do this? Am I barking up the wrong tree?

Answer 1

Another easy way to get started with this, before you decide which objects will need access and which won’t, is to simply make a public static class to hold this and other global objects. Something like:

public static class Globals {     public static Foo foo = new Foo(); }