COOKIES
Cookie is a small text file which is
created by the client's browser and also stored on the client hard disk by the
browser. It does not use server memory. Generally a cookie is used to identify
users.
A cookie is a small file that stores user
information. Whenever a user makes a request for a page the first time, the
server creates a cookie and sends it to the client along with the requested
page and the client browser receives that cookie and stores it on the client
machine either permanently or temporarily (persistent or non persistence). The
next time the user makes a request for the same site, either the same or
another page, the browser checks the existence of the cookie for that site in
the folder. If the cookie exists it sends a request with the same cookie, else
that request is treated as a new request.
Types of Cookies
1. Persistence Cookie: Cookies which you can set an expiry date time are called persistence
cookies. Persistence cookies are permanently stored till the time you set.
Example to create persistence cookie
Response.Cookies[“name”].Value = “Vishwa Academy”;
Response.Cookies[“name”].Expires =
DateTime.Now.AddMinutes(10);
In above code we use Response.Cookies object
for create Cookie.
In above example we have set 10 Minute time for Expire Cookie, we can retrieve
cookie values up to 10 minutes, after 10 minutes the cookies automatically
expires.
2. Non-Persistence
Cookie: Non
persistence cookies are not permanently stored on the user client hard disk
folder. It maintains user information as long as the user accesses the same
browser. When user closes the browser the cookie will be discarded. Non
Persistence cookies are useful for public computers.
Example to create non-persistnce cookie
HttpCookiestrname = new HttpCookie(“name”);
strname.Value = “Vishwa Academy”;
Response.Cookies.Add(strname);
Limitation of cookies: The number of cookies allowed
is limited and varies according to the browser. Most browsers allow 20 cookies
per server in a client's hard disk folder and the size of a cookie is not more
than 4096 bytes or 4 KB of data that also includes name and value data.
Creating
Cookies:
HttpCookie StudentCookies = new HttpCookie("studData");
StudentCookies.Value = TextBox1.Text;
StudentCookies.Expires = DateTime.Now.AddHours(1);
Response.Cookies.Add(StudentCookies);
Response.Cookies["studData"].Value = TextBox1.Text;
Response.Cookies["studData"].Expires = DateTime.Now.AddDays(1);
Type
3:(Writing Multiple values in single cookie)
Response.Cookies["studData"]["RollNumber"] = TextBox1.Text;
Response.Cookies["studData"]["FirstName"] = "Vishwanath";
Response.Cookies["studData"]["MiddleName"] = "D";
Response.Cookies["studData"]["LastName"] = "Panchal";
Response.Cookies["studData"]["TotalMarks"] = "350";
Response.Cookies["studData"].Expires = DateTime.Now.AddMinutes(5);
Reading
Cookies:
For Type 1 and Type 2
For Type 3
str1= Request.Cookies["StudentCookies"]["RollNumber"];
str1= str1 + " " + Request.Cookies["StudentCookies"]["FirstName"];
str1= str1 + " " + Request.Cookies["StudentCookies"]["MiddleName"];
str1= str1 + " " + Request.Cookies["StudentCookies"]["LastName"];
str1= str1 + " " + Request.Cookies["StudentCookies"]["TotalMarks"];
Label1.Text = str1;
Example:
To Create Cookie ASPX
File:
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Enter Data: <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<br />
<asp:Button ID="btnCreate" runat="server" Text="CreateCookeis"
onclick="btnCreate_Click" />
</div>
</form>
</body>
</html>
To Create Cookie ASPX.CS
File:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
{
protected void Page_Load(object
sender, EventArgs e)
{
protected void btnCreate_Click(object
sender, EventArgs e)
{
//Create
Cookies
Response.Cookies["mydata"].Value = TextBox1.Text;
Response.Cookies["mydata"].Expires = DateTime.Now.AddMinutes(10);
Response.Redirect("http://localhost:50618/WebSite18/ReadCookies.aspx");
}
}
To Read Cookie ASPX
File:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server" ></asp:Label>
</div>
</form>
</body>
</html>
To Read Cookie ASPX.CS
File:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
{
protected void Page_Load(object
sender, EventArgs e)
{
string
str;
str = Request.Cookies["mydata"].Value;
Label1.Text = "Your
Cookie Data is " + str;
}
}
