xfapdf.cs

using System.IO;
using TallComponents.PDF;
using TallComponents.PDF.Forms.Fields;
using TallComponents.PDF.JavaScript;

Console.WriteLine(System.IO.Directory.GetCurrentDirectory());

using (FileStream inFile = new FileStream(@"./nIVD_eSTAR_40.pdf", FileMode.Open, FileAccess.Read))
{
    Document document = new Document(inFile);
    document.Fields.Changed += Fields_Changed;

    Console.WriteLine("Before we click the button!");
    for (int i = 0; i < document.Fields.Count; i++)
    {
        Console.WriteLine("\t" + document.Fields[i].FullName);
    }

    RadioButtonField radioField = document.Fields["root[0].ApplicationType[0].USA[0].ATRadioButton110[0]"] as RadioButtonField;
    radioField.Value = "1";
    // radioField.CalculateAction.JavaScript.Run(document);

    Console.WriteLine("After we click the button!");
    for (int i = 0; i < document.Fields.Count; i++)
    {
        Console.WriteLine("\t" + document.Fields[i].FullName);
    }
    
    using (FileStream outFile = new FileStream(@"./nIVD_eSTAR_40-filled.pdf", FileMode.Create, FileAccess.Write))
    {
        document.Write(outFile);
    }

}

Console.WriteLine("All done!");

static void Fields_Changed(FieldCollection sender, FieldsChangedEventArgs e)
{
    Console.WriteLine(e.Added.Length);
}