State Management in ASP.NET
State management:
1)http is a stateless protocol
2)http behavior is go, get and forget
Go->the client request will be taken to webserver by establishing connection
Get->the response will be taken from webserver to client
Forget->the connection will be closed between browser and webserver
3)http as a stateless protocol can be considered as an advantage, it will reduce burden on webserver
4)the requirement is website should able to remember user information. The solution is statemanagement
5)website remembering users information is called “statemanagement”.
Asp.net is providing different techniques to work with statemanagement
1)viewstate
2)cookies
3)session
4)application
5)cache
Viewstate:
1)viewstate can be used to maintain user information towards a webpage for different postback submissions
2)the user information can be controls data[state] (or) normal data[variables]
3)controls state will be maintained implicitly with the help of viewstate. Developer can handle normal data[variables] using viewstate object
Storing data into viewstate:
Viewstate[“varname”]=value;
The value will be stored in the form of an object [variable will be declared with object datatype, this allows storing any type of data]
Reading data from viewstate:
Viewstate[“varname”]->it returns value in the form of an object, it can be type casted to required type
EX:
Viewstate[“varname”].Tostring()->it will convert an object type data into string type.
(datatype) viewstate[“varname”]->it will convert an object into specified datatype
Creating website to work with viewstate
Goto visual studio
Start->run->devenv
It will display main window of visual studio
File menu->new->website->visual c#->select asp.net empty website
Weblocation->e:\aspnet\viewstatesite[drive:\dir\websitename]
Visual studio create a folder with website name, in this folder website related files will be placed
Add webform
Goto view menu and select solution explorer
Right click on website path and select add new item
Select webform
Give name as login.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="login.aspx.cs" Inherits="login" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
</form>
</body>
</html>
goto design part
User name
Password
|
Login |
Label3
Textbox1 properties:
Id-t1
Textbox2 properties:
Id-t2
Textmode-password
Button1 properties:
Text-login
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (t1.Text == "peers" && t2.Text == "info") Server.Transfer("welcome.aspx");
else
{
// invalid login parameters
if (ViewState["n"] == null) ViewState["n"] = 1;
else
ViewState["n"] = (int)ViewState["n"] + 1;
Label3.Text = "number of attempts failed:" + ViewState["n"].ToString();
}
}
}
Add webform
Goto view menu and select solution explorer
Right click on website path and select add new item
Select webform
Give name as welcome.aspx
Goto design part
Place a label with text welcome to mysite
Goto view menu and select solution explorer
Right click on login.aspx set as start page
Goto contrl F5
Note:
1)viewstate information will be maintained as part of webpage output with in hiddenfield
2)hiddenfield will maintain viewstate information [variable data] in a encrypted format
3)textbox without visibility is called “hidden field”
