title: Send POST request with the same name of parameters in C#
body: <p>I want to send POST request with many parameters with the same name: </p>
  
  <pre><code>FormUrlEncodedContent content = new FormUrlEncodedContent(new [] {
    new KeyValuePair &lt; string, string &gt; ("group_id", "344"),
      new KeyValuePair &lt; string, string &gt; ("group_id", "20"),
      new KeyValuePair &lt; string, string &gt; ("group_id", "456")
  });
  
  
  HttpResponseMessage response = await _httpClient.PostAsync("http://localhost/api", content);
  </code></pre>
  
  <p>But if I use above request I get response only for the first group_id (with 344 ID). Do you have any idea how I can obtain <em>"group_id[]=344&amp;group_id[]=20&amp;group_id[]=456"</em> using <em>FormUrlEncodedContent</em> ?</p>