从 MVC 5 控制器中发送 API POST 请求以及 url 中的所有数据

Send API POST request with all data in url from within MVC 5 controller

我正在联系外部 API,仅通过 url:

发布的值除外
https://api.solo.com.hr/racun?token:aisudfhlashf&tip_usluge:....

我已经构建了要附加到 url 的字符串:

PrepareData(Model model)
{
    string s = "?";
    s += "token:" + lApp.GetSoloApiToken() + "&";
    s += "tip_usluge:" + "1" + "&";
    s += "prikazi_porez:" + "1" + "&";
    ...
    return(s);
}

我找不到除了 url 或字符串格式的数据之外的方法。我试过 WebClient() 和 HttpClient()

string data = PrepareData(model);
var response = client.UploadValues("https://api.solo.com.hr/racun" + data); // of course doesn't work

null 作为内容参数传递给 HttpClient.PostAsync(...) 将发送 POST 带有空正文的请求

HttpClient client;
...
var response = await client.PostAsync("https://api.solo.com.hr/racun" + data, null);