#问题：
当向一个https的url上发送请求，报错：未能创建 SSL/TLS 安全通道；
using (WebClient client = new WebClient()){ ???string address="https://xxx.com"; ???client.Headers.Add(HttpRequestHeader.ContentType, "text/xml"); ???System.Text.ASCIIEncoding ?encoding=new System.Text.ASCIIEncoding(); ???var response = client.UploadData(address, "POST", encoding.GetBytes(msg));}#原因：
ssl证书不受信任，验证失败；
#解决方案：
请求之前，进行如下设置；
ServicePointManager.ServerCertificateValidationCallback += new System.Net.Security.RemoteCertificateValidationCallback(bypassAllCertificateStuff);private static bool bypassAllCertificateStuff(object sender, X509Certificate cert, X509Chain chain, System.Net.Security.SslPolicyErrors error){ ??return true;}简写
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };整合
1 public class Test 2 { 3 ????public void TestFun 4 ????{ 5 ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult); 6 using (WebClient client = new WebClient()) 7 { 8 ??? ?string address="https://xxx.com";
9 ?client.Headers.Add(HttpRequestHeader.ContentType,"text/xml");10 ??? System.Text.ASCIIEncoding ?encoding=new System.Text.ASCIIEncoding();11 ??? var response = client.UploadData(address, "POST", encoding.GetBytes(msg));12 }13 ????} 14 ????private bool CheckValidationResult(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certificate, System.Security.Cryptography.X509Certificates.X509Chain chain, System.Net.Security.SslPolicyErrors errors)15 ????{ ??// 总是接受 认证平台 服务器的证书16 ????????return true;17 ????}18 }【SSL】WebClient 请求 https 页面出错:未能创建 SSL/TLS 安全通道
原文地址：https://www.cnblogs.com/willingtolove/p/9403796.html