自定义支持Cookie的WebClient

WebClientWithCookie.cs

/// <summary>
    /// 自定义的WebClient，支持Cookie，在多个请求之间可以重复利用
    /// 作者：陈希章
    /// 邮箱：ares@xizhang.com
    /// 时间：2017年9月17日
    /// </summary>
    public class WebClientWithCookie : WebClient
    {
        /// <summary>
        /// 默认构造器，创建一个空白的CookieContainer
        /// </summary>
        public WebClientWithCookie()
        {
            this.CookieContainer = new CookieContainer();
        }

        /// <summary>
        /// 带参数的构造器，允许从外部传入一个CookieContainer，这样就能实现跨WebClient共享Cookie了
        /// </summary>
        /// <param name="cookie"></param>
        public WebClientWithCookie(CookieContainer cookie)
        {
            this.CookieContainer = cookie;
        }

        /// <summary>
        /// 这个属性用来保存cookiecontainer（容器）
        /// </summary>
        public CookieContainer CookieContainer { get; set; }


        public void HeadRequest(string url)//专门的一个用来支持HEAD操作的方法
        {
            var request = GetWebRequest(new Uri(url));
            request.Method = "HEAD";
            request.GetResponseAsync();
        }
        /// <summary>
        /// 这个方法可以支持自定义Request，构造出来这个对象后，还可以自己添加其他的设置，例如HEADER等信息
        /// </summary>
        /// <param name="url">访问地址</param>
        /// <param name="method">HTTP Method</param>
        /// <returns></returns>
        public HttpWebRequest BuildRequest(string url,string method)
        {
            var request = GetWebRequest(new Uri(url));
            request.Method = method;
            return request as HttpWebRequest;
        }

        /// <summary>
        /// 重写这个方法以便支持Cookie
        /// </summary>
        /// <param name="address"></param>
        /// <returns></returns>
        protected override WebRequest GetWebRequest(Uri address)
        {


            var request=  base.GetWebRequest(address);
            if(request is HttpWebRequest)
            {
                var httpRequest = request as HttpWebRequest;
                httpRequest.CookieContainer = CookieContainer;
            }

            return request;
        }
    }