Good practice to put all global/common objects & methods in App class?

Hello!

I was wondering if it is a good practice to keep the globally required objects and methods inside the App class (public sealed partial class App : Application). If yes, should I make these all members static and access them anywhere as App.value=20; App.method();, or should I keep them non-static and use them with an object such as,

app = (App)Application.Current;

app.value=20;

app.method();

I understand both of them works just fine. But which way is a good programming practice, or there's no harm and either is fine?

Thanks!

- Prateek Jain