C＃：System.Net.WebException：底层连接已关闭
我有以下代码：
String url = // a valid url String requestXml = File.ReadAllText(filePath);//opens file , reads all text and closes it byte[] bytes = System.Text.Encoding.ASCII.GetBytes(requestXml); HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); request.Credentials = new NetworkCredential("DEFAULT\\Admin", "Admin"); request.ContentType = "application/xml"; request.ContentLength = bytes.Length; request.Method = "POST"; request.KeepAlive = false; Stream requestStream = request.GetRequestStream(); requestStream.Write(bytes, 0, bytes.Length); requestStream.Close(); HttpWebResponse response = (HttpWebResponse)request.GetResponse(); Stream responseStream = response.GetResponseStream(); return new StreamReader(responseStream).ReadToEnd(); 在运行期间，我在尝试读取HTTPWebResponse时遇到以下exception：
System.Net.WebException：基础连接已关闭：接收上发生意外错误。
—> System.IO.IOException：无法从传输连接读取数据：已建立的连接已被主机中的软件中止。
—> System.Net.Sockets.SocketException：已建立的连接被主机中的软件中止
在System.Net.Sockets.Socket.Receive（Byte []缓冲区，Int32偏移量，Int32大小，SocketFlags socketFlags）
在System.Net.Sockets.NetworkStream.Read（Byte []缓冲区，Int32偏移量，Int32大小）
在System.Net.Sockets.NetworkStream.Read（Byte []缓冲区，Int32偏移量，Int32大小）
在System.Net.PooledStream.Read（Byte []缓冲区，Int32偏移量，Int32大小）
在System.Net.Connection.SyncRead（HttpWebRequest请求，布尔userRetrievedStream，布尔probeRead）
在读取之前不要关闭流。 这应该工作：
String url = // a valid url String requestXml = File.ReadAllText(filePath);//opens file , reads all text and closes it byte[] bytes = System.Text.Encoding.ASCII.GetBytes(requestXml); HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); request.Credentials = new NetworkCredential("DEFAULT\\Admin", "Admin"); request.ContentType = "application/xml"; request.ContentLength = bytes.Length; request.Method = "POST"; request.KeepAlive = false; using (Stream requestStream = request.GetRequestStream()) { requestStream.Write(bytes, 0, bytes.Length); using (HttpWebResponse response = (HttpWebResponse)request.GetResponse()) { using (Stream responseStream = response.GetResponseStream()) { using (StreamReader streamReader = new StreamReader(responseStream)) { return streamReader.ReadToEnd(); } } } }
添加这行代码解决了我的问题：
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
这取自： https ： //our.umbraco.com/forum/using-umbraco-and-getting-started/74628-the-underlying-connection-was-closed-an-unexpected-error-occurred-on-a -发送