Delete cookie on clicking sign out

Question

I am creating the cookie using the code below, How to read the txtusername value in another page and how to delete the cookie when I click sign out(code for sign out). I am new to programming please help.

  string cookiestr;
            HttpCookie ck;
            tkt = new FormsAuthenticationTicket(1, txtUserName.Value, DateTime.Now,
            DateTime.Now.AddMinutes(30), chkPersistCookie.Checked, "your custom data");
            cookiestr = FormsAuthentication.Encrypt(tkt);

            ck = new HttpCookie(FormsAuthentication.FormsCookieName, cookiestr);
            if (chkPersistCookie.Checked)
                ck.Expires = tkt.Expiration;
            ck.Path = FormsAuthentication.FormsCookiePath;
            Response.Cookies.Add(ck);

Answer 1

You should never store password as a cookie. That's a very big security threat. To delete a cookie, you really just need to modify and expire it. You can't really delete it, i.e. remove it from the user's disk. Check out this documentation.

Here is a sample:

 HttpCookie aCookie;
    string cookieName;
    int limit = Request.Cookies.Count;
    for (int i=0; i<limit; i++)
    {
        cookieName = Request.Cookies[i].Name;
        aCookie = new HttpCookie(cookieName);
        aCookie.Expires = DateTime.Now.AddDays(-1); // make it expire yesterday
        Response.Cookies.Add(aCookie); // overwrite it
    }