.NET Framework - ASP NET 2.0 Cookie

Asked By icanhelp3

08-May-08 07:08 AM

I have a C# utility that runs in ASP website. When user logs in the
ASP code writes the cookie using Response.Cookie. I try to read the
same cookie in C#. I am unable to read it in C# code.

I am using Request.Cookies["cookiename"].Value.ToString(). I can read
the same cookie in ASP code.
If I say Request.Cookies("CookieName") in ASP that works fine..

06-May-08 01:06 PM

re:
!> I am using Request.Cookies["cookiename"].Value.ToString()

Try either of these approaches :

1.

if(Request.Cookies["cookieName"] != null)
Label1.Text = Server.HtmlEncode(Request.Cookies["cookieName"].Value);

2.
if(Request.Cookies["cookieName"] != null)
{
HttpCookie aCookie = Request.Cookies["cookieName"];
Label1.Text = Server.HtmlEncode(aCookie.Value);
}

Before trying to get the value of a cookie, you should make sure that the cookie exists;
if the cookie does not exist, you will get a NullReferenceException exception.

Notice also that the HtmlEncode method was called to encode the contents of a cookie
before displaying it in the page. This makes certain that a malicious user has not added
executable script into the cookie.



Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
======================================

08-May-08 07:08 AM

I know how to read the cookie. The problem is when I try to read it in
C# it always returns null. In ASP it returns the value of the cookie.

06-May-08 01:37 PM

re:
!> I know how to read the cookie.
!> The problem is when I try to read it in C# it always returns null.

Then, either the code you're using doesn't read the cookie properly,
or the cookie isn't being set correctly.

Have you tried the code I posted to read cookies ?

As for setting cookies, here's 2 sample C# code fragments :

1.
Response.Cookies["userName"].Value = "patrick";
Response.Cookies["userName"].Expires = DateTime.Now.AddDays(1);

2.
HttpCookie aCookie = new HttpCookie("lastVisit");
aCookie.Value = DateTime.Now.ToString();
aCookie.Expires = DateTime.Now.AddDays(1);
Response.Cookies.Add(aCookie);

How are you setting the cookie ?
Are you expiring the cookie ?



Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
======================================

06-May-08 01:42 PM

I'm really not sure you can do that... ASP And ASP.NET are separate
engines... I'm even surprised you don't get an exception as from the point
of view of the C# utility (how do you run this one ? This is exposed as a
com object ?) there is IMO no current (ASP.NET) request...

You may want to elaborate a bit on your architecture and/or what you are
trying to do...

--
Patrice

17a3fab7-c885-4fa2-9e93-5fc45bb037d3@v26g2000prm.googlegroups.com...

06-May-08 01:50 PM

Or do you mean you just transfer control from an ASP page to an ASPX page as
Juan seems to have understood from your description ?

As you talked about a "C# utility" rather than about an ASP.NET page, I was
thinking that this "C# utility" was directly called from the ASP page during
the same request. As i said earlier you may want to elaborate a bit on your
architecture so that we are 100 % sure about how ASP and ASP.NET interacts
in your design...

--
Patrice

discussion : D9051416-6E51-4DA2-9371-B22FD0665AEE@microsoft.com...

06-May-08 02:48 PM

Cookies should be able to read regardless
of the language/platform used to write them.




Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
======================================

06-May-08 06:25 PM

Typo alert...

That should have been :

Cookies should be able to be read regardless
of the language/platform used to write them.




Juan T. Llibre, asp.net MVP
asp.net faq : http://asp.net.do/faq/
foros de asp.net, en español : http://asp.net.do/foros/
======================================

06-May-08 07:15 PM

Correct, though some languages like C# are case-sensitive, which may be the
issue here...


--
Mark Rae
ASP.NET MVP
http://www.markrae.net

07-May-08 08:08 PM

Make sure the Path property of your cookie is set. , e.g. "/". There are
minor inconsistencies in classic ASP cookies and  ASP.NET cookies.
Peter

07-May-08 08:12 PM

To be more specific:

Cookie Interop - ASP -->ASPX:

There is a change in cookie behavior between ASP and ASPX. In brief: If you
do NOT
specifically set a cookie path, ASP will automatically set the path to:
your web application's name --
If you do NOT specifically set a path, ASPX will automatically set the path
to:
your server name --

To make ASP behave like ASPX, then add --
Response.Cookies("...").Path = "/" -- to your ASP code

To make ASPX behave like ASP, then add --
MyCookieObject.Path = "/AppName" -- to your ASPX code.

--Peter

28-Apr-10 07:55 AM

What is a Cookie ?



A Cookie is an object is used to store the sort amount of data onto client end. It executes on server and resides on client browser.



How does Cookie work ?



when users request a page from your site, your application sends not just a page, but a cookie containing some data. When the user's browser gets the page, the browser also gets the cookie.Later, the user requests a page from your site again.If the cookie exists, the browser sends the cookie to your site along with the page

request.



What are different type of Cookie ?



Session Cookie : This Cookie will expire once the browser is closed.

Persistent Cookie :  This Cookie will exists in browser till the time of expire.

How much can we store in a Cookie ?



Cookie specifications suggest that browsers should support a minimal number of cookies . In particular, an internet browser is expected to be able to store at least 300 cookies of four kilobytes each (both name and value count towards this 4 kilobyte limit), and at least 20 cookies per server or domain, so it is not a good idea to use a different cookie for each variable that has to be saved. It's better to save all needed data into one single cookie.