Global Variables vs. ASP.NET Session State

Question

This is probably going to sound rather naive, but I'm developing a web application that spans multiple pages. All of these pages instantiate the same class object w/ methods that accesses a CMS using their API. Currently, when a user starts creating content, I'm storing variables like a folder ID where the content is located in a Session variable.

My question is this: Can I instantiate a single instance of a class that can be used across all pages without having to do it on every page? If so, would each person accessing that page be given their own version of the class? I assume that using static variables and methods isn't the way to go since they are shared in memory. And also, where/how is something declared if it is going to be used globally in a Web Application in a .net C# application?

Answer 1

I recommend making a base class which inherits from System.Page. Then have your page code behind inherit from that.

Then, inside the base class, create a property that is a reference to your object. Like this, for example:

public class BasePage : System.Web.UI.Page
{
    public Foo CurrentFoo
    {
        get
        {
            return (Foo)Session["FooSessionObject"];
        }
        set
        {
            if(Session["FooSessionObject"] == null)
            { 
                // instantiate a new one
                Session["FooSessionObject"] = new Foo();
            }
            Session["FooSessionObject"] = value;
        }
    }
}

Then, from anywhere in any page, just do a CurrentFoo. and you will have access to any of the properties.

This makes for nice and clean code behind.