在WCF中读取调用者的IP地址(OperationContext为null)？

string clientIP = ServiceSecurityContext.Current.PrimaryIdentity.Name;

string clientIP = OperationContext.Current.IncomingMessageProperties[RemoteEndpointMessageProperty.Name].ToString();

string clientIP = HttpContext.Current.Request.UserHostAddress;

string clientIP = System.Net.Dns.GetHostAddresses(OperationContext.Current.IncomingMessageHeaders.To.Host)[0].ToString();