A web client implementation that extends the System.Net.WebClient by storing cookies for recurring requests.

ExtendedWebClient.cs

/// <summary>
    /// A web client implementation that extends the System.Net.WebClient by storing cookies for recurring requests.
    /// </summary>
    public sealed class ExtendedWebClient : WebClient
    {
        public CookieContainer CookieContainer { get; set; }

        protected override WebRequest GetWebRequest(Uri address)
        {
            var webRequest = base.GetWebRequest(address);

            var httpWebRequest = webRequest as HttpWebRequest;

            if (httpWebRequest != null)
            {
                (httpWebRequest).CookieContainer = CookieContainer;
            }

            return webRequest;
        }
    }