sample code to rename pdf fields created with period/full stops in fieldname

renamepdffields.vb

Function ChangeFieldNamesInForm()
        Try
            Dim sourcePDF As String = "source.pdf"
            Dim outputPDF As String = "destination.pdf"
            Dim fsw As FileStream = New FileStream(outputPDF, FileMode.OpenOrCreate, FileAccess.ReadWrite)
            Dim reader As PdfReader = New PdfReader(sourcePDF)
            Dim stamper As PdfStamper = New PdfStamper(reader, fsw)
            Dim root As PdfDictionary = reader.Catalog()
            Dim form As PdfDictionary = root.GetAsDict(PdfName.ACROFORM)
            Dim fields As PdfArray = form.GetAsArray(PdfName.FIELDS)
            Dim stamperfields As AcroFields = stamper.AcroFields
            Dim fieldkey As String
            Dim test As Boolean = True
            Dim fieldcount As Integer = stamperfields.Fields.Keys.Count - 1
            Dim fieldsarray(fieldcount) As String
            Dim i As Integer = 0
            Dim item As AcroFields.Item
            Dim dic As PdfDictionary
            Dim rect As PdfArray
            Dim newname As String
            Dim name As String
            Dim llx As String
            Dim lly As String
            Dim ulx As String
            Dim uly As String
            Dim fieldtype As String
            Dim field As PdfFormField = Nothing
            '================================================================
            For Each fieldkey In stamperfields.Fields.Keys
            'you need to keep a period "." for checkbox and radio button groups
                newname = fieldkey.Replace(".", "_")
                newname = newname.Replace("cb_", "cb.")
                newname = newname.Replace("rb_", "rb.")
                newname = newname.Replace("_", "")
                fieldsarray(i) = fieldkey
                i += 1
                item = stamperfields.Fields(fieldkey)
                dic = item.GetValue(0)
                rect = dic.Get(PdfName.RECT)
                llx = rect.ArrayList(0).ToString
                lly = rect.ArrayList(1).ToString
                ulx = rect.ArrayList(2).ToString
                uly = rect.ArrayList(3).ToString
                name = dic.Get(PdfName.T).ToString
                Dim newrect As iTextSharp.text.Rectangle = New iTextSharp.text.Rectangle(llx, lly, ulx, uly)
                fieldtype = dic.Get(PdfName.FT).ToString
                Select Case fieldtype
                    Case "/Tx"
                            'add the new field to the form
                            Dim newfield As iTextSharp.text.pdf.TextField
                            newfield = New iTextSharp.text.pdf.TextField(stamper.Writer, newrect, newname)
                            field = newfield.GetTextField
                    Case "/Btn"
                        Dim responselength As Integer = newname.LastIndexOf(".")
                        Dim buttonresponse As String = Mid(newname, responselength + 2)
                        Dim checkbutton = New RadioCheckField(stamper.Writer, newrect, newname, buttonresponse)
                        field = checkbutton.CheckField
                    Case Else
                End Select
                '========================================
                'need to work out how to determine the page number but for now go with hard coded
         
                stamper.AddAnnotation(field, 1)
            Next

            'remove the original fields from the stamper
            For j = 0 To fieldcount
                'do not remove form instance id
                    test = stamperfields.RemoveField(fieldsarray(j))
                    If test = True Then
                        Console.Write(fieldsarray(j) & " removed")
                    End If
            Next
            Console.Write("all fields removed")
            stamper.Close()
            reader.Close()
        Catch ex As Exception
            Console.Write(ex.Message)
            Return False
        End Try
        Return True
    End Function