program.cs

using System;
using System.IO;
using System.Net.Http.Headers;
using System.Net.Http;

namespace CSHttpClientSample
{
    static class Program
    {
        static void Main()
        {
            Console.Write("Enter the path to a JPEG image file:");
            string imageFilePath = Console.ReadLine();

            MakeRequest(imageFilePath);

            Console.WriteLine("\n\n\nWait for the result below, then hit ENTER to exit...\n\n\n");
            Console.ReadLine();
        }

        static byte[] GetImageAsByteArray(string imageFilePath)
        {
            FileStream fileStream = new FileStream(imageFilePath, FileMode.Open, FileAccess.Read);
            BinaryReader binaryReader = new BinaryReader(fileStream);
            return binaryReader.ReadBytes((int)fileStream.Length);
        }

        static async void MakeRequest(string imageFilePath)
        {
            var client = new HttpClient();

            // Request headers - replace this example key with your valid key.
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "2e4167d9f21e432686ee677952e39cf4");

            // NOTE: You must use the same region in your REST call as you used to obtain your subscription keys.
            //   For example, if you obtained your subscription keys from westcentralus, replace "westus" in the 
            //   URI below with "westcentralus".
            string uri = "https://westus.api.cognitive.microsoft.com/emotion/v1.0/recognize?";
            HttpResponseMessage response;
            string responseContent;

            // Request body. Try this sample with a locally stored JPEG image.
            byte[] byteData = GetImageAsByteArray(imageFilePath);

            using (var 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");
                response = await client.PostAsync(uri, content);
                responseContent = response.Content.ReadAsStringAsync().Result;
            }


            // System.IO.File.WriteAllText(@"C:\test\test1.json", responseContent);
            using (System.IO.StreamWriter file =
            new System.IO.StreamWriter(@"C:\test\test1.json", true))
            {
                file.WriteLine(responseContent);
            }

            //A peak at the JSON response.
            Console.WriteLine(responseContent);

           


        }
    }
}