C#访问Http及https操作

public class ApiResult
        {
            public int statusCode;
            public string result;
            public string errcode;
            public string memo;
        }
        private ApiResult PostUrl(string apiPath, string postData, WebHeaderCollection headers, string method, string contenttype, string p12certfile, string cerpassword)
        {
            string url = string.Format("https://{0}:{1}{2}", this.m_pltip, this.m_pltPort, apiPath);
            if (isHttp)
            {
                url = string.Format("http://{0}:{1}{2}", this.m_pltip, this.m_pltPort, apiPath);
            }
            ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(ValidateServerCertificate);
            ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
            HttpWebRequest httpRequest = (HttpWebRequest)HttpWebRequest.Create(url);

            X509Certificate2 cerCaiShang = n