Using Cookies in ASP.NET

What are cookies?

If you are a ASP developer, you probably already know what are cookies and how to use them in ASP. Just to recap - Cookies are small files stored on client machine which contain a piece of information. Cookies are typically used to store personalization information, user's nick name, his preferences etc. In this short code illustration we will see how to write and read cookies in ASP.NET.

Cookies - ASP way

You need to use cookies collection of Response and Request object in order to write and read cookies respectively. Let us quickly see how you created cookies using ASP :

Writing cookies to client - ASP Way

Response.Cookies("username")="Bipin"

Response.Cookies("useraddress")("city")="Mumbai"

Response.Cookies("useraddress")("country")="India"

Reading cookies - ASP Way

myvar=Request.Cookies("username")

myvar1=Request.Cookies("useraddress")("city")

myvar2=Request.Cookies("useraddress")("country")

Cookies - ASP.NET way

ASP.NET provides more user friendly way to manipulate cookies. It has a namespace called System.Web which provides HttpCookie class. The class has properties matching with traditional ASP. Let us understand this with examples :

<%@ language="VB"%>
<%@ import namespace="System" %>
<%@ import namespace="System.Web" %>
<%@ import namespace="System.Web.HttpCookie" %>

<script runat="server">

public sub page_load(sender as object,e as eventargs)
	if request.cookies("myname")=null then
		dim cookie as HttpCookie
		cookie=new HttpCookie("myname")
		cookie.value="bipin"
		response.appendcookie(cookie)
		label1.text="Cookie Written"
	else
		label1.text="Cookie already exists : "
		label1.text=label1.text &
		request.cookies("myname").value
	end if
end sub

</script>

<asp:label id=label1 text="Cookie Written" runat=server />

Create multiple value cookies

<%@ language="VB"%>
<%@ import namespace="System" %>
<%@ import namespace="System.Web" %>
<%@ import namespace="System.Web.HttpCookie" %>

<script runat="server">

public sub page_load(sender as object,e as eventargs)
	if request.cookies("mychoices")=null then
		dim cookie as HttpCookie
		cookie=new HttpCookie("mychoices")
        cookie.Values.Add("Color","blue")
        cookie.Values.Add("Font","Verdana")
		response.appendcookie(cookie)
		label1.text="Cookie Written"
	else
		label1.text="Cookie already exists : "
		label1.text=label1.text &
request.cookies("mychoices").values("Color")
		label1.text=label1.text &
request.cookies("mychoices").values("Font")
	end if
end sub

</script>

<asp:label id=label1 text="Cookie Written" runat=server />

Both the example are very straight forward and need no extra explanation.