我想循环调用一次Azure Face API，然后将所有结果保存在数组中

Question

我正在调用Face API和该API的图像，并在Json中获取结果。我想在循环中再调用一次此api，然后将所有图像的所有结果保存在数组中的循环中。不幸的是我做不到。

        foreach (var allwords in ViewBag.sentence)
        {
            string imgpath = Server.MapPath("~/Content/Images/") + allwords + ".png";

            HttpClient client = new HttpClient();

            // Request headers.
            client.DefaultRequestHeaders.Add(
                "Ocp-Apim-Subscription-Key", subscriptionKey);

            // Request parameters. A third optional parameter is "details".
            string requestParameters = "&returnFaceAttributes=smile," +
                "emotion";

            // Assemble the URI for the REST API Call.
            string uri = uriBase + "?" + requestParameters;

            HttpResponseMessage response;

            // Request body. Posts a locally stored JPEG image.
            byte[] byteData = GetImageAsByteArray(imgpath);

            using (ByteArrayContent content = new ByteArrayContent(byteData))
            {
                // This example uses content type "application/octet-stream".
                // The other content types you can use are "application/json"
                // and "multipart/form-data".
                content.Headers.ContentType =
                    new MediaTypeHeaderValue("application/octet-stream");

                // Execute the REST API call.
                response = await client.PostAsync(uri, content);

                // Get the JSON response.
                string contentString = await response.Content.ReadAsStringAsync();
                // var data = JsonConvert.DeserializeObject(contentString);
                //array to store every image result
                string results = contentString;

              // return Json(result, JsonRequestBehavior.AllowGet);

            }

我只得到一个图像结果，这是Web API调用的最后一个图像。我正在循环调用所有图像，但无法保存在最后一个图像之前调用的图像的结果。