How does this Singleton-like web class persists session data, even though session is not updated in
- by Micah Burnett
Ok, I've got this singleton-like web class which uses session to maintain state. I initially thought I was going to have to manipulate the session variables on each "set" so that the new values were updated in the session. However I tried using it as-is, and somehow, it remembers state.
For example, if run this code on one page:
UserContext.Current.User.FirstName = "Micah";
And run this code in a different browser tab, FirstName is displayed correctly:
Response.Write(UserContext.Current.User.FirstName);
Can someone tell me (prove) how this data is getting persisted in the session? Here is the class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
public class UserContext
{
private UserContext() { }
public static UserContext Current
{
get
{
if (System.Web.HttpContext.Current.Session["UserContext"] == null)
{
UserContext uc = new UserContext();
uc.User = new User();
System.Web.HttpContext.Current.Session["UserContext"] = uc;
}
return (UserContext)System.Web.HttpContext.Current.Session["UserContext"];
}
}
private string HospitalField;
public string Hospital
{
get { return HospitalField; }
set
{
HospitalField = value;
ContractField = null;
ModelType = null;
}
}
private string ContractField;
public string Contract
{
get { return ContractField; }
set
{
ContractField = value;
ModelType = string.Empty;
}
}
private string ModelTypeField;
public string ModelType
{
get { return ModelTypeField; }
set { ModelTypeField = value; }
}
private User UserField;
public User User
{
get { return UserField; }
set { UserField = value; }
}
public void DoSomething()
{
}
}
public class User
{
public int UserId { get; set; }
public string FirstName { get; set; }
}
I added this to a watch, and can see that the session variable is definitely being set somewhere:
(UserContext)System.Web.HttpContext.Current.Session["UserContext"];
As soon as a setter is called the Session var is immediately updated:
set
{
HospitalField = value; //<--- here
ContractField = null;
ModelType = null;
}
