private void VisibleTopChoiceHelper(int topVisible, int expected, String file) {
Document document = new Document();
FileStream fos = new FileStream(OUTPUT_FOLDER + file, FileMode.Create);
PdfWriter writer = PdfWriter.GetInstance(document, fos);
document.Open();
TextField textField = new TextField(writer, new Rectangle(380, 560, 500, 610), "testListBox");
textField.Visibility = BaseField.VISIBLE;
textField.Rotation = 0;
textField.FontSize = 14f;
textField.TextColor = BaseColor.MAGENTA;
textField.BorderColor = BaseColor.BLACK;
textField.BorderStyle = PdfBorderDictionary.STYLE_SOLID;
textField.Font = BaseFont.CreateFont(BaseFont.TIMES_ROMAN, BaseFont.WINANSI, BaseFont.EMBEDDED);
textField.BorderWidth = BaseField.BORDER_WIDTH_THIN;
writer.RunDirection = PdfWriter.RUN_DIRECTION_LTR;
textField.Choices = new String[] {"one", "two", "three"};
textField.ChoiceExports = new String[] {"1", "2", "3"};
//choose the second item
textField.ChoiceSelection = 1;
//set the first item as the visible one
textField.VisibleTopChoice = topVisible;
Assert.AreEqual(expected, textField.VisibleTopChoice);
PdfFormField field = textField.GetListField();
writer.AddAnnotation(field);
document.Close();
// compare
CompareTool compareTool = new CompareTool();
String errorMessage = compareTool.CompareByContent(OUTPUT_FOLDER + file, CMP_FOLDER + file, OUTPUT_FOLDER, "diff");
if (errorMessage != null) {
Assert.Fail(errorMessage);
}
}