Do all instances of the same ASPX page share the same static field?

Question

Let's consider this page's code-behind:

public partial class Products : Page
{
    private static SomeClass SharedField;

    public Product()
    {
        // ... Some logic
    }
}

Do all Products pages instances share the same SharedField, I know this is a basic concept of static fields. But in this case, really? all users can have access (and can't have their own instance of) to the same static field on the website-level?

If so, in what aspects this would used by the web developer? or is this non-recommended practice?

score 2 · Answer 1 · edited May 23 '17 at 12:29

2

SharedField will be available in one instance for the entire life-cycle of the web site.

To read a bit more about it, see this answer.

edited May 23 '17 at 12:29

Community

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1

answered Feb 09 '11 at 21:31

Filip Ekberg

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score 2 · Accepted Answer · answered Feb 09 '11 at 21:33

Yes, there will be a single instance of that static field for all users, but only within a single worker process. If you have web farms/web gardens, they will each have their own static instance. If the worker process restarts, you'll get a new static instance.

You'll have to use locking around that shared field to ensure thread safety.

As for why to use that, I'm not sure, I never do it. The best example I can give you is the built-in static HttpContext.Current, which gives you access to the Request, Response, etc.

score 0 · Answer 3 · answered Feb 09 '11 at 21:38

0

A better practice would be to store your object in the Application state.

Application["MyObject"] = new SomeClass();

answered Feb 09 '11 at 21:38

GavinH

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Believe it or not, Microsoft says to use a static instead. http://stackoverflow.com/questions/4879023/what-is-the-life-span-of-a-field-in-a-static-class/4879119#4879119 – Greg Feb 09 '11 at 21:39
Wow, that really surprised me! I suppose the Application object has been superseded by the Cache object anyway. – GavinH Feb 09 '11 at 21:44

Do all instances of the same ASPX page share the same static field?

3 Answers3