CODEWITHSUNDEEP
c#pdfitext
UberGrunk
UberGrunk

Reputation: 63

Filling pdf field that takes value from other field

I know there are many similar questions on here, i've tried several of them but have not managed to solve the problem(and many of them are still unanswered after several years).

My problem is that i can not set the value of the two fields at the top of the second page named "form1[0].sida2[0].flt_datSidhuvud[0]" and "form1[0].sida2[0].flt_txtPersonNrBrukare[0]", they both have a field with same name but different prefix on the first page and from the research i've done this might be causing the problem but the suggested solutions have not worked for me.

If i fill in the form manually with for example Acrobat Reader the values that are input in the fields on page one automatically appear in the fields on page two and the other way around.

Here is an example of the code i use to try and fill in the two fields

MemoryStream output = new MemoryStream();
FileStream fs = File.Open(pdfTemplatePath, FileMode.Open, FileAccess.Read);
PdfReader reader = new PdfReader(fs);
fs.Close();
PdfStamper stamper = new PdfStamper(reader, output);
var formFields = stamper.AcroFields;

formFields.SetField("form1[0].sida2[0].flt_datSidhuvud[0]", "2016-12"));
formFields.SetField("form1[0].sida2[0].flt_txtPersonNrBrukare[0]", data.SocialSecurityNumber);//data.SocialSecurityNumber is a string

stamper.FormFlattening = true;
stamper.Close();
reader.Close();

The result is that it fills in the value of the fields on the first page only.

Link to PDF

From my research this question here on SO was the most promising but the suggested solution(to remove XFA) doesn't seem to work in my case.

Upvotes: 0

Views: 877

Answers (1)

mkl
mkl

Reputation: 95963

In general

If (AcroForm) form fields have different full names, they are separate fields.

A behavior as you describe (filling one field in Adobe Reader upon losing focus automatically fills another one, too) can be achieved using JavaScript actions. But filling in these fields using iText does not trigger any JavaScript events. Thus, in general you have to fill in both (AcroForm) fields.

Your case is special

Your case is slightly different, though:

  • Your PDF contains a hybrid form, both present as AcroForm form and as XFA form, and iText sometimes in the 5.x versions got fitted with a certain amount of XFA support. In particular in case of hybrid forms,
    • whenever the value of a field is retrieved, it first is looked up in the XFA form data elements; and
    • whenever a field value is set, it is set both in a single matching AcroForm field and in the XFA form data elements.
  • In the AcroForm representation of your form, the flt_datSidhuvud and flt_txtPersonNrBrukare fields on page 2 (which you do not explicitly fill) are empty and don't even have an appearance stream.
  • In the XFA representation of your form both flt_datSidhuvud form fields are backed by a single data element, and so are both flt_txtPersonNrBrukare form fields.

Furthermore, your case is special because you flatten the form. If you did not flatten id, only the values in the fields of the AcroForm fields on the first page and the XFA data fields would be set, not the AcroForm fields on the second page.

Form flattening has also been substantially improved during the 5.x versions.

Why does it work

While flattening your hybrid form, the fields on page two get their values:

While flattening the still empty flt_datSidhuvud and flt_txtPersonNrBrukare AcroForm fields on page two, iText determines that they do not have any appearance streams yet to flatten into the page content and, therefore, tries to create appearance streams for them.

To create these appearances, iText first retrieves the value of each field. As mentioned above, this means that the value in the XFA form is looked up first which is the same for both the fields on page one and two. Thus, here the value you set for the field on the first page is retrieved and used for building the appearance on the second page!

Why didn't it work for you initially

In comments you said that you mostly used the older 4.1.6.0 iTextSharp version, not the current 5.5.11.0 one. As explained above, the automatic fill-in on your second page depends on the iText XFA support and form flattening improvements both of which were introduced during the 5.x versions.

Thus, your initial attempts to run the code from your question did not result in filled-in fields on page 2 because the older iTextSharp versions simply did not implement support for that.

Upvotes: 1

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