解決https調用出現【基礎連接已經關閉: 未能為 SSL/TLS 安全通道建立信任關系】錯誤

在HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(url);前面添加

ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);

CheckValidationResult方法

 public static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
{  // 總是接受  
　　return true;
}