string requestUri = "http://www.example.com"; string requestBodyString = "请求正文字符串。"; string contentType = "text/plain"; string requestMethod = "POST"; byte[] responseBody; byte[] requestBodyBytes = Encoding.UTF8.GetBytes(requestBodyString); using (var client = new WebClient()) { client.Headers[HttpRequestHeader.ContentType] = contentType; responseBody = client.UploadData(requestUri, requestMethod, requestBodyBytes); }