using System;

using System.Net.Http;

using System.Reflection;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        string FilePath = "file3.txt";

        RequestJson requestJson = new RequestJson();

        requestJson.uploadFile = FilePath; // string Path of file

        requestJson.userName = "Nation";

        requestJson.email = "Nation@xyz.com";

        var content = new MultipartFormDataContent();

        foreach (PropertyInfo prop in typeof(RequestJson).GetProperties(BindingFlags.Instance|BindingFlags.GetProperty|BindingFlags.Public))

        {

            if (prop.Name == "uploadFile")

            {

                var fileContent = new ByteArrayContent(new byte[10], 0, 0); // Replace with Your File Content

​

                content.Add(fileContent, prop.Name, prop.GetValue(requestJson).ToString());

            }

            else

            {

                content.Add(new StringContent(JsonConvert.SerializeObject(prop.GetValue(requestJson))), prop.Name);

            }

        }

        Console.WriteLine(JsonConvert.SerializeObject(content, Formatting.Indented));

    }

}

​

public class RequestJson

{

    public string uploadFile { get; set; }

    public string userName { get; set; }

    public string email { get; set; }

}