How to read the values of radio button in the pdf?

I am trying to read a radio buttons using following code:
Field f = PDFDocument.GetField("radioButtonName");
if (f.GetType() == Field.Type.e_radio) {
         pdftron.SDF.Obj values = f.GetValue();


f.GetValue() is null and I am unable to get its button value.

I want to get the button value, which I can use it later on to set
that radio button in another copy of pdf.

Thank you.

To obtain the value for radio or check-box field you can use

bool val = f.GetValueAsBool().

Alterantively you couls use f.GetValueAsString() which would also give
you the current appearance for the radio/check.

Q: This was very helpful, thank you. We have the list-box controls
correctly now. Do you have an equivalent code sample for radio
Also, I looked in the documentation but there doesn't seem to be a
for the fields in these objects that PDFTron provides. Is there some
of the documentation that we missed?
A: Radio buttons have only on/off state. You could GetValueAsBool() to
find out if the given radio button field is selected or not.

a listing for the fields in these objects that

These entries are part of PDF specification (