在HttpClient C#中发送嵌套的JSON和文件

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

HttpClient client = new HttpClient();

var jsonData = new
{
    key1 = "value1",
    key2 = "value2"
};

var fileStream = new FileStream("path_to_file", FileMode.Open);

var content = new MultipartFormDataContent();

// 添加JSON数据
var jsonContent = new StringContent(JsonConvert.SerializeObject(jsonData));
jsonContent.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");
content.Add(jsonContent, "json");

// 添加文件
var fileContent = new StreamContent(fileStream);
fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");
content.Add(fileContent, "file", "filename.ext");

var response = await client.PostAsync("https://example.com/api", content);

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

public class Program
{
    public static async Task Main(string[] args)
    {
        using (HttpClient client = new HttpClient())
        {
            var jsonData = new
            {
                key1 = "value1",
                key2 = "value2"
            };

            using (var fileStream = new FileStream("path_to_file", FileMode.Open))
            {
                var content = new MultipartFormDataContent();

                // 添加JSON数据
                var jsonContent = new StringContent(JsonConvert.SerializeObject(jsonData));
                jsonContent.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");
                content.Add(jsonContent, "json");

                // 添加文件
                var fileContent = new StreamContent(fileStream);
                fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");
                content.Add(fileContent, "file", "filename.ext");

                var response = await client.PostAsync("https://example.com/api", content);

                if (response.IsSuccessStatusCode)
                {
                    var responseContent = await response.Content.ReadAsStringAsync();
                    Console.WriteLine(responseContent);
                }
                else
                {
                    Console.WriteLine("Request failed with status code: " + response.StatusCode);
                }
            }
        }
    }
}