State Management in ASP.NET

As we all know, HTTP or HTTPS is stateless protocol. It just cleans up or we can say removes all the resources/references that were serving a specific request in the past.

Stateless means, whenever we visit a website, our browser communicates with the respective server depending on our requested functionality or the request. In this case HTTP/HTTPs doesn't remember what website or URL we visited, or in other words we can say it doesn't hold the state of a previous website that we visited before closing our browser, that is called stateless.

So our browsers are stateless.

State Management Types

Client-side | Techniques

View State

View State is the method to preserve the Value of the Page and Controls between round trips. It is a Page-Level State Management technique. View State is turned on by default and normally serializes the data in every control on the page regardless of whether it is actually used during a post-back.Please keep in mind though, that while cookies and sessions can be accessed from all your pages on your website, ViewState values are not carried between pages.

Hidden field

Hidden Field is non visual control in ASP.NET where we can save the value. This is one of the types of client-side state management tools. It stores the value between the roundtrip. Anyone can see Hidden Field details by simply viewing the source of document.

Cookies

Cookies is a small piece of information stored on the client machine. Its is used to store user preference information like Password, City, SessionId etc on client machines. We need to import namespace called Systen.Web before we use cookie(HttpCookie).

Control State

The control state is a way to save a control’s state information when the EnableViewState property is turned off. Unlike ViewState a developer can’t turn off control state. The control state can be implemented only in controls that you implement. ControlState is used to store small amounts of critical information. Heavy usage of ControlState can impact the performance of application because it involves serialization and deserialization for its functioning.

There are two methods(SaveControlState and LoadControlState) which we have to implement in your custom control and on OnInit method of the control we need to add the call for the Page.RegisterRequiresControlState() method with the instance of the control to register.

   public class ControlWebControl : Control
   {
       private string _strStateToSave;
       protected override void OnInit(EventArgs e)
       {
           Page.RegisterRequiresControlState(this);
           base.OnInit(e);
       }
       protected override object SaveControlState()
       {
           return _strStateToSave;
       }
       protected override void LoadControlState(object state)
       {
           if (state != null)
           {
               _strStateToSave = state.ToString();
           }
       }
   }

Query Strings

Query string is one of the techniques in Web applications to send data from one page to another. A query string consists of two parts, field and value, and each of pair separated by ampersand (&). The ?(question mark in a query string indicates the beginning of a query string and it's value.

Server-side | Technique

Session State

OutProc

ASP.NET session state is designed to enable you to easily store user session data in different sources for your ASP.NET applications. By default, session state values and information are stored in memory within the ASP.NET process. Alternatively, you can store session data in a SQL Server database, where it can be shared by multiple Web servers. For more information about session state, see Implementing a Session-State Store Provider and Session-State Modes.