c# WebRequest using WebBrowser cookie

    public CookieContainer GetCookieContainer()
    {
        CookieContainer container = new CookieContainer();

        foreach (string cookie in webBrowser1.Document.Cookie.Split(';'))
        {
            string name = cookie.Split('=')[0];
            string value = cookie.Substring(name.Length + 1);
            string path = "https://stackoverflow.com/";
            string domain = ".google.com"; //change to your domain name
            container.Add(new Cookie(name.Trim(), value.Trim(), path, domain));
        }

        return container;
    }

This will work on most sites, however sites that use subdomains might be a problem.