C#socket发送HTTP请求页面一直返回空值，求个大神帮忙看一下

string sendStr= @"http://10.158.15.115:8084/CtrlCenter/ASM?data=%3CMessage%20Device=%220000001370%22%3E%3CRequest%20Name=%22OBDGetTime%22/%3E%3C/Message%3E";
            StringBuilder sb = new StringBuilder();
            sb.AppendLine("post /CtrlCenter/ASM?data=" + GetTimeXml().Replace(" ", "%20") + "HTTP/1.1\r\n");
            sb.AppendLine("Host:"+hostName+":"+port);
            sb.AppendLine("Content-Type: application/x-www-form/r/n");
            sb.AppendLine("\r\n");
            byte[] bytesSendStr = new byte[2048];
            //将发送内容字符串转换成字节byte数组 
            bytesSendStr =Encoding.UTF8.GetBytes(sb.ToString());

这个是写的头，GetTimeXml(),得到的是%3CMessage%20Device=%220000001370%22%3E%3CRequest%20Name=%22OBDGetTime%22/%3E%3C/Message%3E/

完整的StringBuilder sb是

{get /CtrlCenter/ASM?data=%3CMessage%20Device=%220000001370%22%3E%3CRequest%20Name=%22OBDGetTime%22/%3E%3C/Message%3E/HTTP/1.1

}

返回一直是空值。第一次用请大神勿喷

网页测试是这样的