test.cs

TXTextControl.LoadSettings loadSettings = new TXTextControl.LoadSettings()
{
  ApplicationFieldFormat = TXTextControl.ApplicationFieldFormat.MSWordTXFormFields
};

using (TXTextControl.ServerTextControl serverTextControl = 
  new TXTextControl.ServerTextControl())
{
  serverTextControl.Create();
  serverTextControl.Load("contentcontrols.docx", 
    TXTextControl.StreamType.WordprocessingML, loadSettings);

  foreach (FormField ff in serverTextControl.FormFields)
  {
    Console.WriteLine(ff.Text);
  }
}