test.cs

private void FlattenFormFields(ServerTextControl textControl)
{
  int fieldCount = textControl.FormFields.Count;

  for (int i = 0; i < fieldCount; i++) {
    TextFieldCollectionBase.TextFieldEnumerator fieldEnum =
      textControl.FormFields.GetEnumerator();
    fieldEnum.MoveNext();

        TXTextControl.FormField curField = (TXTextControl.FormField)fieldEnum.Current;
    textControl.FormFields.Remove(curField, true);
  }
}