Using cookie in asp.net mvc c#

Question

I want to register the parameter of a few pages in my web site using cookie. I tried the below code but not like what I want :

 public ActionResult Index(int? dep, int? cat)
 {
   ......
   string theDept = Request.QueryString["dep"];
   HttpCookie cookie = new HttpCookie("search");
   cookie.Values["dep_name"] = theDept;
   cookie.Expires = DateTime.Now.AddDays(1);
   Response.Cookies.Add(cookie);
   return View();
 }

I read it in site.master :

<% 

HttpCookie cookie = Request.Cookies["search"] ;

if ((cookie != null) && (cookie.Value != ""))
{
    Response.Write(cookie.Values["dep_name"].ToString() + "---" +   
    cookie.Values["cat_name"].ToString() + "---" + cookie.Values["brand"].ToString());
}
%>

Problem: When I click to another page that Request.QueryString["dep"] is null, the cookie that I display is null to.

How to store it in the cookie without losing while we not yet clear the cookie?

Answer 1

I m not sure I understand if this is a question about how to properly send cookies to the client or some bug with your querystring params. So I ll post the proper way of sending cookies and feel free to correct me if I misunderstood.

In any case though, I believe this:

HttpCookie cookie = new HttpCookie("search");

will reset the search cookie

To get a cookie:

HttpCookie cookie = HttpContext.Request.Cookies.Get("some_cookie_name");

To check for a cookie's existence:

HttpContext.Request.Cookies["some_cookie_name"] != null

To save a cookie:

HttpCookie cookie = new HttpCookie("some_cookie_name");
HttpContext.Response.Cookies.Remove("some_cookie_name");
HttpContext.Response.SetCookie(cookie );

Answer 2

i have organised the cookie fetching and inserting in an organized manner such that it can be used throughout the application. for that purpose i put two methods SetCookie and GetCookie.

You can simply put this class in your code and work out.

Here i put my class with the static methods

public class CookieStore
{
    public static void SetCookie(string key, string value, TimeSpan expires)
    {
        HttpCookie encodedCookie = HttpSecureCookie.Encode(new HttpCookie(key, value));

        if (HttpContext.Current.Request.Cookies[key] != null)
        {
            var cookieOld = HttpContext.Current.Request.Cookies[key];
            cookieOld.Expires = DateTime.Now.Add(expires);
            cookieOld.Value = encodedCookie.Value;
            HttpContext.Current.Response.Cookies.Add(cookieOld);
        }
        else
        {
            encodedCookie.Expires = DateTime.Now.Add(expires);
            HttpContext.Current.Response.Cookies.Add(encodedCookie);
        }
     }
    public static string GetCookie(string key)
    {
        string value = string.Empty;
        HttpCookie cookie = HttpContext.Current.Request.Cookies[key];

        if (cookie != null)
        {
            // For security purpose, we need to encrypt the value.
            HttpCookie decodedCookie = HttpSecureCookie.Decode(cookie);
            value = decodedCookie.Value;
        }
        return value;
    }

}

using these you can easily store values in cookie and fetch value whenever required

using these methods is as simple as

For Setting Cookie:

CookieStore.SetCookie("currency", "GBP", TimeSpan.FromDays(1)); // here 1 is no of days for cookie to live

For Getting Cookie:

string currency= CookieStore.GetCookie("currency");