Question

I have this code

//file Globals.cs in App_Code folder
public class Globals
{
    public static string labelText = "";
}

and a simple aspx page which has textbox, label and button. The CodeFile is:

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Label1.Text = Globals.labelText;       
    }

    protected void Button1_Click1(object sender, EventArgs e)
    {
        Globals.labelText = TextBox1.Text;
    }
}

That is when I click on the button the Globals.labelText variable initializes from the textbox; the question is: why when I open this page in another browser the label has that value, which I set by the first browser, that is the static member is common for the every users. I thought that the every request provides in the individual appDomain which created by the individual copy of IIS process. WTF?

Answer 1

No, static in this case is static in that manner only for the lifecycle of the process the request lives on. So this variable will be static the entire time you’re processing a single request. In order to have a “static” variable in the manner you describe, you’d have to make it an application variable. Something like this:

//file Globals.cs in App_Code folder
public class Globals
{
    // I really recommend using a more descriptive name
    public static string LabelText
    {
        get
        {
            return Application("LabelText") ?? string.Empty;
        }
        set
        {
            Application("LabelText") = value;
        }
    }
}

By making it an application variable it should survive multiple page requests. A vulnerability it has though is that it will not survive an application pool recycle, and for large applications this can be problematic. If you truly want this variable to behave in a static manner reliably you’re probably better off storing its state in a database somewhere.