HttpWebRequest 请求第三方https接口，一直提示未能创建 SSL/TLS 安全通道! 证书验证创建委托一直返回true 也不行。
public bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors) { return true; }
ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);
设置ServicePointManager.SecurityProtocol也不行，试过Ssl3，Tls,Tls11,Tls12
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
导入证书依然不行
request.ClientCertificates.Add(new X509Certificate(AppDomain.CurrentDomain.BaseDirectory + "sinho1.cer"));
测试完整代码
HttpWebRequest request = null;
request = (HttpWebRequest)HttpWebRequest.Create(this._UriString);
request.ContentType = "application/x-www-form-urlencoded";
request.Accept = "text/html, application/xhtml+xml, */*";
request.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36";
request.AllowAutoRedirect = this._AllowAutoRedirect;
request.CookieContainer = new CookieContainer();
request.Referer = this._Referer;
request.Timeout = 120000;
request.ReadWriteTimeout = 120000;
request.ServicePoint.Expect100Continue = true;
request.ServicePoint.ConnectionLimit = 1024;
request.KeepAlive = true;
//request.ClientCertificates.Add(new X509Certificate(AppDomain.CurrentDomain.BaseDirectory + "sinho1.cer"));
//request.ProtocolVersion = HttpVersion.Version10;
if (this.Header != null && this.Header.Count > 0)
{
foreach (var item in Header)
{
SetHeaderValue(request.Headers, item.key, item.value);
}
}
if (this._Accept != null)
request.Accept = this._Accept;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; //协议按需选择，不行就都试一遍
ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);
最终找到一个最简单的解决办法：将.net 版本设置.NET Framework 4.6及以上，完美解决！
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原文链接：https://blog.csdn.net/m0_37693130/article/details/85317380