How to properly do this C# MultiPartFormDataContent API Call?

Question

I am currently trying to make an api call in c# using a MultiPartFormDataContent but I keep getting the following error:

"Response: {"statusCode":400,"error":"Bad Request","message":""Image file" must be of type object","validation":{"source":"payload","keys":["images"]}}"

This is my Code:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;

namespace Example
{
    public class Test
    {
        public static void Main(string[] args)
        {
            Task<string> test = testFunction();
            Console.WriteLine("Result: " + test.Result);
        }

        public static async Task<string> testFunction()
        {
            const string file = "C:\\ExamplePath\\image_1.jpeg";
            const string URL = "https://example-api?api-key=example-key";

            string boundary = "---8d0f01e6b3b5dafaaadaad";
            MultipartFormDataContent multipartContent = new MultipartFormDataContent(boundary);

            var streamContent = new StreamContent(File.Open(file, FileMode.Open));
            var stringContent = new StringContent("flower");

            multipartContent.Add(stringContent, "organs");
            multipartContent.Add(streamContent, "images");

            try
            {
                HttpClient httpClient = new HttpClient();
                HttpResponseMessage response = await httpClient.PostAsync(URL, multipartContent);

                Console.WriteLine("Response: " + await response.Content.ReadAsStringAsync());

                if (response.IsSuccessStatusCode)
                {
                    string content = await response.Content.ReadAsStringAsync();
                    Console.WriteLine("IN METHIOD: " + content);
                    return content;
                }
                return null;
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
                return null;
            }
        }
    }
}

It's obviously a problem with how I am trying to do the api call but I don't know how to do it with an object instead like mentioned the error message.

Answer 1

This link has some good examples and where I actually got my code snippet from below.

Here's a basic example of using MultiFormDataContent:

HttpClient httpClient = new HttpClient();
MultipartFormDataContent form = new MultipartFormDataContent();

form.Add(new StringContent(username), "username");
form.Add(new StringContent(useremail), "email");
form.Add(new StringContent(password), "password");            
form.Add(new ByteArrayContent(file_bytes, 0, file_bytes.Length), "profile_pic", "hello1.jpg");
HttpResponseMessage response = await httpClient.PostAsync("PostUrl", form);

response.EnsureSuccessStatusCode();
httpClient.Dispose();
string sd = response.Content.ReadAsStringAsync().Result;

I hope this helps or points you in the right direction.