I want to retrieve the values of filled form fields on this PDF. This is my code:

public virtual void ManipulatePdf(String src, String dest) {
            PdfDocument pdf = new PdfDocument(new PdfReader(src), new PdfWriter(dest));
            List<PdfAnnotation> annotArray = new List<PdfAnnotation>(pdf.GetFirstPage().GetAnnotations());

            Console.WriteLine(annotArray.Count);
            for (int i = 0; i < annotArray.Count; i++)
            {
                Console.Write(annotArray[i]);
                Console.Write(", ");
                Console.Write(annotArray[i].GetTitle());
                Console.Write(", ");
                if (annotArray[i].GetContents() is null){Console.Write("null");}
                else {Console.Write(annotArray[i].GetContents());}
                Console.WriteLine("");
            }
            pdf.Close();
        }

The code prints out 145 widget annotations like so: iText.Kernel.Pdf.Annot.PdfWidgetAnnotation, CharacterName, null

All the annotations have their correct name, but no content, all null. How do I get the strings and check values contained within?