State ManagementNot like the State of Virginia

What is State in ASP.NET?Services (like web services) are Stateless.

This means if you make a second request to a server, it will not remember what your last request was.

ASP.NET adds the concept of State to web pagesThis allows you to have objects persist across

page requests

Why Use State?Almost every page online uses state

It’s hard to find a meaningful static web pageState allows pages to dynamically respond to

different users and eventsExample Uses:

Enforcing page authenticationRemembering your shopping cartPersonalized search results

State ObjectsSimply put: a collection of objects

Collection<string, object>Ex: Session[“UserId”] = 4;

Objects:SessionViewStateApplicationCacheCookies

SessionLifetime:

From the first request til timeout/cleared sessionIt is possible for session to last longer than the

server host if stored using SQL Session StorageScope:

Only to the owner of the sessionPersists across pages. Inaccessible from other

sessionsUsage:

Accessing data shared across pages (ex. Login info)

ViewStateLifetime:

The life of the pageRendered to the page

Scope: Just that request. Does not persist across pages or

across sessionsRebuilt for the following requests

Usage:Control selection data (form data, checkbox

selections, drop down list selections, etc.)

ViewState<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTc0NTQxNTAwMWQYAQUeX19Db250cm9sc1JlcXVpcmVQb3N0QmFja0tleV9fFgMFKWN0bDAwJENvbnRlbnRQbGFjZUhvbGRlcjEkQ2hlY2tCb3hMaXN0MSQwBSljdGwwMCRDb250ZW50UGxhY2VIb2xkZXIxJENoZWNrQm94TGlzdDEkMQUpY3RsMDAkQ29udGVudFBsYWNlSG9sZGVyMSRDaGVja0JveExpc3QxJDFN/3diiSeYfuwsveCFZkB8GZhziyh9fxFB4N3DEHI9Ow==" />

ApplicationLifetime:

The life of the application Persists until the service restarts

Scope:The entire applicationAll users in all sessions have access to this

objectUsage:

Application wide settingsConfiguration settings

CacheLifetime:

Until the cached object expiresScope:

Application wideAll users in all sessions have access to this

objectUsage:

Stored commonly accessed data

Cookies?

CookiesLifetime:

Lifetime of the cookie Be kind to your users. Don’t forget to set an

expiration date on your cookiesScope:

The browserCan be accessed on any page in the cookie’s

domain (determined by browser security settings)Usage:

Quenching random hunger cravings

Don’t do this:

Strongly Typed StateRemember: a collection of objects

Collection<string, object>You can store any object in these collectionsWhat if you want to restrict the types objects

stored in the State?Enforce type in a typeless environment

Removes confusion about what’s stored in the object

Strongly Typed Statepublic int UserId{ get { if (!(Session["UserId"] is int)) Session["UserId"] = -1; return (int)Session["UserId"]; } set { Session["UserId"] = value; }}