This document discusses state management in ASP.NET web applications. It begins by explaining that browsers are generally stateless and do not remember information between requests. It then discusses how state management preserves information in ASP.NET applications using techniques like view state, cookies, query strings, application state, and session state. It provides details on different state management techniques, including advantages and disadvantages of client-side techniques like view state, cookies, and query strings versus server-side techniques.

1. State
Management
Dr. Monika Patel

2. State Overview
• Browsers are generally stateless.
• Stateless means, whenever we visit a website, our browser communicates
with the respective server depending on our requested functionality or
the request.
• The browser communicates with the respective server using the HTTP or
HTTPs protocol.
• But after that response, what's next or what will happen when we visit
that website again after closing our web browser?
• In this case HTTP/HTTPs doesn't remember what website or URL we
visited.
• 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.

3. State Management
• State management is very important and useful in ASP.NET.
• ASP.NET State management is a preserve state control and object in an
application because ASP.NET web applications are stateless.
• A new instance of the Web page class is created each time the page is
posted to the server.
• If a user enters information into a web application, that information
would be lost in the round trip from the browser (MSDN).
• State management maintains and stores the information of any user till
the end of the user session.

4. Types of State Management
State Management
Client- Side
Management
ViewState QueryString Cookies
Server-Side
Managanement
Application State Session State

5. Client-Side State Management
•Whenever we use Client-Side State
Management, the state related
information will directly get stored on the
client-side.
•That specific information will travel back
and communicate with every request
generated by the user then afterwards
provides responses after server-side
communication.

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7. Server-Side State Management
•In Server-Side State Management all the
information is stored in the user
memory.
•Due to this functionality there is more
secure domains at the server side in
comparison to Client-Side State
Management.

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9. Client-side Techniques
•Client-Side State Management techniques
are,
a) View State
b) Hidden field
c) Cookies
d) Control State
e) Query Strings

10. ViewState
•ViewState is a important client side state
management technique.
•View State is the method to preserve the Value of
the Page and Controls between round trips.
•Preserving the value of page controls between
client to server and server to client is
called "roundtrip".
•It stores the page or control value in the mode of
hidden fields.

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• The ViewState is a dictionary kind of object which stores the
value on the basis of KEY/VALUE.
• By default, the ViewState is enabled, but we can enable or
disable ViewState on Page level or Control level.
There are two properties on Page Level
1) ViewStateMode
2) EnableVIewState
3) ViewStateEncryptionMode = “Always” / “Auto” / “Never”
• There is one property on Control Level.
• EnableViewState = “True” / “False”

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• Each web page and the controls on the page have the
EnableViewState property.
• User can set ViewState on/off for each control using EnableViewState
property.
• ASP.NET framework uses the ViewState property to automatically
save the values of the Web page and each control on the Web page
prior to rendering the page.
• User can also disable ViewState for the entire page by adding
EnableViewState= false to @page directive.

13. Enable/Disable Viewstate
• <%@ Page Language="C#" AutoEventWireup="true"
CodeFile=“WebStud.aspx.cs" EnableViewState="true"
Inherits="WebApplication1.Student" %>

14. How to store the value in ViewState?
• ViewState stores the value in a Key/Value pair basis.
Syntax
ViewState[“KeyName”] = Object / String .etc.

15. Data Types Can Store In Viewstate
• Integers
• String
• Boolean
• Array/ArrayList
• Hash Table

16. Features Of View State
1) Retains the value of the Control after post-back without using a
session.
2) Stores the value of Pages and Control Properties defined in the
page.
3) Creates a custom View State Provider that lets you store View
State Information in a SQL Server Database or in another data
store.

17. Advantages of View State
1) Easy to Implement.
2) No server resources are required: The View State is contained in a
structure within the page load.
3) Enhanced security features: It can be encoded and compressed or
Unicode implementation.

18. Disadvantages of View State
1) Security Risk: The Information of View State can be seen in the page
output source directly. You can manually encrypt and decrypt the
contents of a Hidden Field, but It requires extra coding. If security is a
concern then consider using a Server-Based state Mechanism so that
no sensitive information is sent to the client.
2) Performance: Performance is not good if we use a large amount of
data because View State is stored in the page itself and storing a
large value can cause the page to be slow.
3) Device limitation: Mobile Devices might not have the memory
capacity to store a large amount of View State data.
4) It can store values for the same page only.

19. When We Should Use View State
• When the data to be stored is small.
• Try to avoid secure data.

20. Querystring
• A query string is one of the techniques in Web applications to
send data from one webform to another through the URL.
• 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.
• There is a limit on the Query string length.
• Hence, Query strings cannot be used to send very long data.
• Some browsers and client devices impose a 2083 character
limit on the length of the URL.
• Most browsers impose a limit of 255 characters on URL length.
• Query strings are visible to the user, hence should not be used
to send sensitive information such as a username and password
but we can also encrypt query values.

21. Advantages
• Simple to Implement
• No server resources are required
• Widespread support
• Almost all browsers and client devices support using query strings to
pass values.
• Query strings contain the HTTP request for a specific URL.

22. Disadvantages
• Cross paging functionality makes it redundant
• Easily modified by end user
• Potential security risks due to Human Readable: The information in
the query string is directly visible to the user via the browser's user
interface.
• Limited capacity: Some browsers and client devices impose a 2083-
character limit on the length of URLs.

23. Sending Only One Querystring Value
• Sender Page:
Response.Redirect(“PageName+Keyname=Value”);
• Receiver Page:
Str = Request.QueryString[“Keyname”];

24. Sending More Than One Querystring Value
• Sender Page:
Response.Redirect(“PageName+Keyname1=Value1&KeyName2=
Value2”);
• Receiver Page:
Str1 = Request.QueryString[“Keyname1”];
Str2 = Request.QueryString[“Keyname2”];

25. Cookies
• A cookie is a small amount of data that is stored either in a text file on the
client file system or in-memory in the client browser session.
• This file is located on client machines "C:Document and
SettingsCurrently_Login userCookie" path.
• It is used to store user preference information like Username,
Password,City and PhoneNo etc on client machines.
• We need to import namespace called Systen.Web.HttpCookie before we
use cookie.

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• Usually a cookie can have a maximum size of 4KB.
• A particular named cookie can store a single value or a collection of
name/value pairs.
• Each cookie must have a unique name.
• User can set a cookie’s date and time expiration.
• If user does not set the cookie’s expiration, the cookie is created but
it is not stored on the user’s hard disk.

27. Types of Cookies
There are two types of cookies:
1.Persistence Cookie
2.Non-Persistence Cookie
1. Persistence Cookie
Cookies which have an expiry date time are called
persistence cookies.
This types of cookies are stored on user’s hard
drive permanently till the date time we set.

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2. Non-Persistence Cookie
• This types of cookies are not permanently stored on user hard drive.
• It stores the information up the user accessing the same browser.
• When user close the browser the cookies will be automatically
deleted.

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• Store Value:
HttpCookie Cookiename = new HttpCookie(“Storecookiename”);
Cookiename.Values[“Keyname”] = Value;
Cookiename.Expires = DateTime.Now.AddDays(1);
Response.Cookies.Add(Cookiename);
• Fetch Value:
Variable name = Request.Cookies[“Storecookiename”].Values["KeyName"].ToString();

30. Advantages
• Its clear text so user can able to read it.
• We can store user preference information on the client machine.
• Its easy way to maintain.
• Fast accessing.

31. Disadvantages
• Size limitations
• Most browsers place a 4096-byte limit on the size of a cookie,
although support for 8192-byte
• Most browsers allow only 20 cookies per site; if you try to store
more, the oldest cookies are discarded.
• Cookies can be disabled on user browsers
• Cookies are transmitted for each HTTP request/response causing
overhead on bandwidth.
• Inappropriate for sensitive data due to security is not provided.