title: Return nested arrays in restful api with dotnet core 3.0
body: <p>I'm writing an api call in dotnet core 3.0 and trying to return several objects.  I can return all the objects as long as the information in them is simple.  But, when I have an array of objects (that also contain arrays) the result for that object is empty.</p>
  
  <p>For example, in the following code, the first three items (a c# object, a list of strings and a string) all return values, but the list of chartdatasets is empty in the result of the call.  It is populated when I step through the code on the server side.</p>
  
  <p>Do I have to do something special to return an array of complex objects?</p>
  
  <pre><code>[HttpGet]
  public ActionResult&lt;List&lt;Chart&gt;&gt; GetCharts()
  {
      List&lt;string&gt; axisLabels = new List&lt;string&gt;() {"CLI","MC","MCAL","PAT","PTP","TP"};
      string chartTitle = "Outstanding AR by Fin Group";
      ReturnKey retKey = new ReturnKey() {AuthKey = "asdasdas", Message = "OK"};
  
      List&lt;ChartDataSet&gt; dataSetList = new List&lt;ChartDataSet&gt;();
      List&lt;double&gt; cData = new List&lt;double&gt;();
      cData.Add(37795.59);
      cData.Add(16839.71);
      cData.Add(144.89);
      cData.Add(90);
      cData.Add(216829.68);
      cData.Add(1764.52);
      List&lt;string&gt; cBg = new List&lt;string&gt;();
      dataSetList.Add(new ChartDataSet("Outstanding AR", cBg, cData));
  
      return Ok(new {retKey, axisLabels, chartTitle, dataSetList});
  }
  </code></pre>
  
  <p>The result in postman looks like this.</p>
  
  <pre><code>{
      "retKey": {
          "authKey": "asdasdas",
          "message": "OK"
      },
      "axisLabels": [
          "CLI",
          "MC",
          "MCAL",
          "PAT",
          "PTP",
          "TP"
      ],
      "chartTitle": "Outstanding AR by Fin Group",
      "dataSetList": [
          {}
      ]
  }
  </code></pre>