https://stackoverflow.com/questions/53428338/curl-cmd-and-curl-lib-not-yielding-the-same-results

Program.cs

using System;
using System.Net.Http;

namespace ConsoleApp18
{
    class Program
    {
        static void Main(string[] args)
        {
            var client = new HttpClient();
            client.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0");
            client.DefaultRequestHeaders.Add("Accept-Language", "sv-SE,sv;q=0.8,en-US;q=0.5,en;q=0.3");
            // other headers...

            var postData = "search_text=tomat&dummy=&search_type=all&rec_cats\"%\"5B\"%\"5D=all&submit_search=S\"%\"F6k&recid=&offset=0&searchid=";

            var response = client.PostAsync("https://kokboken.ikv.uu.se/sok.php", new StringContent(postData)).Result;
            var html = response.Content.ReadAsStringAsync().Result;

            Console.WriteLine(html);
        }
    }
}