How to make Chunk underline or bold to display in a pdf

Question

I've been wracking my brain for a couple of days and I am unable to get this working. I am trying to use itextsharp in vb.net and MVC to format a field with bold or underline and then see those changes in the resulting PDF. I am not getting errors but nothing I do changes the fields. The PDF loads fine but the formatting of the fields never changes.

I am trying to convert the text into a pdf paragraph, then loop through its chunks and apply formatting. Then I would like to use "SetField" to fill the field with the resulting string. Something like:

stamper.AcroFields.SetField(fieldName, formattedString)

I am new to this so I am not sure where to troubleshoot further. I have also tried creating a new font and adding that and the document remains unchanged.

I can't upload the PDF file for inspection, but if there is something I should check in the PDF file that might cause this please let me know. The file is in XFA format.

I have the pseudo-code below:

1. The code that calls the GenerateDocument function:

   Dim pdf As Byte()
   pdf = GenerateDocument()
   Return File(pdf, "application/pdf")
   

2. The GenerateDocument function(simplified):

   Public Function GenerateDocument() As Byte()
    Using inStream As New MemoryStream(TemplateBinary) 'the actual pdf binary
     Using outStream As New MemoryStream
   
      Dim pdfReader As New text.pdf.PdfReader(inStream)
      Dim stamper As New PdfStamper(pdfReader, outStream)
      Dim form As AcroFields = stamper.AcroFields
      Dim fieldKeys = form.Fields.Keys
   
      stamper.AddViewerPreference(PdfName.HIDETOOLBAR, New PdfBoolean(True))
      stamper.AddViewerPreference(PdfName.FITWINDOW, New PdfBoolean(True))
      stamper.FormFlattening = False
   
      Dim pdfSegment As Paragraph = CreateSimpleHtmlParagraph("sample text")
      Dim pdfString As New StringBuilder
   
      If pdfSegment.Count > 0 Then
        For counter As Integer = 0 To pdfSegment.Count - 1
   
         Dim para As Paragraph
   
         If pdfSegment(counter).GetType().Name().ToUpper().Contains("PARAGRAPH") Then
           para = pdfSegment(counter)
           For Each ch As Chunk In para
            ch.SetUnderline(0.5F, -1.5F) 'just make everything underline for now
           Next
           pdfString.Append(para.Content)
         End If
   
         If counter < (pdfSegment.Count - 1) Then
          pdfString.AppendLine()
         End If
        Next
   
        form.SetField(xNode.Name, pdfString.ToString())
     End If
     stamper.Close()
     pdfReader.Close()
     Return outStream.ToArray()
   
    End Using
    End Using
   End Function
   

3. The code that makes a PDF paragraph called from the code above

   Private Function CreateSimpleHtmlParagraph(text As String) As Paragraph
   Dim pdfTextSection As New Paragraph()
   
   Using sr As StringReader = New StringReader(text)
   Dim elements As List(Of IElement) = iTextSharp.text.html.simpleparser.HTMLWorker.ParseToList(sr, Nothing)
   
   For Each e As IElement In elements
    pdfTextSection.Add(e)
   Next
   End Using
   
   Return pdfTextSection
   

   End Function

Answer 1

The code listed under 2 is very strange. You create a Paragraph object which consists of some plain text, a font, leading info, indentation info, etc... Then you ask the Paragraph for the plain text without the font info. Elementary logic tells you that the general StringBuilder class is unaware of iTextSharp-specific concepts such as Chunk, Font and underline.

You are also assuming that an ordinary text field is capable of containing rich text. Ordinary text fields are usually defined to contain text in one single font. For instance: "Helvetica" for regular text. Or "Helvetica Bold" for bold text. "Helvetica" and "Helvetica Bold" are two different fonts (of the same family). It is important not to confuse the concept font with the concept font family.

"Underline" is not a quality of the font. Ordinary text fields can't be defined as "the value needs to be underlined".

This means that you'll need a work-around to achieve what you need. This workaround is described in my book, more specifically where I explain the MovieAds example (look here if you need the C# version).

In this example, I don't use the setField() method because of the limitations of ordinary text fields. Instead, I get the position of the field and I add the rich text using the ColumnText object:

AcroFields.FieldPosition f = form.GetFieldPositions(fieldname)[0];
ColumnText ct = new ColumnText(canvas);
ct.SetSimpleColumn(
  f.position.Left, f.position.GetBottom(2),
  f.position.GetRight(2), f.position.Top
);
ct.AddElement(para);
ct.Go();