test.cs

LoadSettings ls = new LoadSettings()
{
  ApplicationFieldFormat = ApplicationFieldFormat.MSWord
};

using (ServerTextControl tx = new ServerTextControl())
{
  tx.Create();
  tx.Load("contentcontrols.docx", StreamType.WordprocessingML, ls);

  foreach (ApplicationField af in tx.ApplicationFields)
  {
    try
    {
      var tempField = ContentControlFieldAdapter.CreateContentControl(af);

      if (tempField is RichTextContentControl ||
        tempField is PlainTextContentControl ||
        tempField is CheckBoxContentControl ||
        tempField is ComboBoxContentControl ||
        tempField is DateContentControl ||
        tempField is DropDownListContentControl)
      {
        Console.WriteLine(tempField.Title);
      }
    }
    catch (Exception ex)
    {
      Console.WriteLine(ex.Message);
    }
  }
}