HttpRequestException: 发送请求时出错。
WebException: 请求被中止: 未能创建 SSL/TLS 安全通道。
方法调用前加以下代码行即可.
System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;
static void Test() { System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12; using (System.Net.Http.HttpClient httpClient = new System.Net.Http.HttpClient()) { httpClient.MaxResponseContentBufferSize = 256000; httpClient.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36"); httpClient.DefaultRequestHeaders.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9"); var param = new Dictionary<string, string> { { "", "<?xml version='1.0'?><message><priority>0</priority></message>" } }; var response = httpClient.PostAsync(@"https://www.baidu.com", new System.Net.Http.FormUrlEncodedContent(param)).Result; Console.WriteLine($"Response:{response.Content.ReadAsStringAsync().Result}"); } }