use a 'dynamic' static property across multiple users?

Question

I'm trying to understand if there is any issue with doing a 'dynamic' static property. Say, I have an ASP.NET Webforms application that deals with Employees in a company. For the sake of this question, lets say this application is built for only one company.

Assume there is a class called Employee. It contains one static property.

public static string CompanyName = "My Company";

Now anywhere on the site if I use CompanyName, it is going to display the same company name for all users. A true static usage.

Now assume I define another property as (Lets say this is for ease of usage across the site so you can just do Employee.LoggedIn. )

public static Employee LoggedIn
{
   get 
   {
     return Session["LoggedInEmployee"] As Employee;
   }
}

This will return different values for different employees based on what user is connected to the site. Does this mean there is a copy of this variable for every user? I know this works as expected but just wondering if it is safe to do this.

EDIT - i'm not looking for better ways to do this. I'm only trying to understand how the static property can hold different values. Someone commented saying the 'get' is a method, but still the property is represented as static.

Answer 1

public static string CompanyName = "My Company";

We don't normally use Singleton in ASP.Net except for IoC container, Logging or Caching.

public Employee static LoggedIn
{
   return Session["LoggedInEmployee"] As Employee;
}

Above code won't even compile.

This will return different values for different employees based on what user is connected to the site. Does this mean there is a copy of this variable for every user? I know this works as expected but just wondering if it is safe to do this.

Based on your question, you want LoggedInEmployee available across your application.

If I understand your question correctly, LoggedInEmployee is the current logged-in employee's information. If so, it shouldn't be shared with other logged-in employee.

Since it is per logged-in employee information, I'll use the alternative approach by storing in HttpContext which is only available to current logged-in employee.

public class MyContext
{
    private MyUser _myUser;

    public static MyContext Current
    {
        get
        {
            if (HttpContext.Current.Items["MyContext"] == null)
            {
                MyContext context = new MyContext();
                HttpContext.Current.Items.Add("MyContext", context);
                return context;
            }
            return (MyContext) HttpContext.Current.Items["MyContext"];
        }
        }

        public MyUser MyUser
        {

            get { return _myUser; }
            set { _myUser = value; }
        }
    }
}

Global.asax

void Application_AuthenticateRequest(object sender, EventArgs e)
{
    if (HttpContext.Current.User != null && 
        HttpContext.Current.User.Identity.IsAuthenticated)
    {
        MyContext.Current.MyUser = 
           YOURCODE.GetUserByUsername(HttpContext.Current.User.Identity.Name);
    }
}

Usage

var user = MyContext.Current.MyUser;

## Back to Original Question ##

public static class EmployeeHelper {
   public static Employee LoggedIn {
      get { return HttpContext.Current.Session["LoggedInEmployee"] as Employee; }
   }
}

Above approach is fine. As long as you do not make like this -

public static class EmployeeHelper {
   // ===== Bad approach =====
   private static HttpSessionState _session = HttpContext.Current.Session;
   public static Employee LoggedIn {
      get { return _session["LoggedInEmployee"] as Employee; }
   }
}