VB.NET Requires Chilkat v11.7.0+

Replace the Second (or Every) Occurrence of a Label in a PDF

See more PDF Text Replacement Examples

Demonstrates the "occurrence" member of a label entry. By default the first occurrence of a label, in reading order across the selected pages, is replaced; "occurrence" can be a number for the nth, or "all" for every occurrence. The invoice template has "Ref:" twice. VB.NET

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  The PDF used in this example is available at invoice_template.pdf

Dim pdf As New Chilkat.Pdf
success = pdf.LoadFile("qa_data/pdf/invoice_template.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
Dim jsonOut As New Chilkat.JsonObject

'  This template's {{placeholders}} are not being filled here: "keep" leaves them as they are
'  (the default, "error", would refuse to apply while a placeholder on the page has no value).
json.UpdateString("unusedPlaceholders","keep")

'  "Ref:" appears twice on the page (A-1 near the top, A-2 below the totals).
'  The default replaces the first occurrence only.
json.UpdateString("labels[0].label","Ref:")
json.UpdateString("labels[0].value","B-7")
success = pdf.TextReplace("check",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("default: " & jsonOut.IntOf("replacements[0].count") & " occurrence replaced")

'  The second occurrence only.
json.UpdateString("labels[0].occurrence","2")
success = pdf.TextReplace("check",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("occurrence 2: " & jsonOut.IntOf("replacements[0].count") & " occurrence replaced")

'  Every occurrence.
json.UpdateString("labels[0].occurrence","all")
success = pdf.TextReplace("apply",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("occurrence all: " & jsonOut.IntOf("replacements[0].count") & " occurrences replaced")

success = pdf.WriteFile("qa_output/invoice_refs.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


'  Sample output:

'  default: 1 occurrence replaced
'  occurrence 2: 1 occurrence replaced
'  occurrence all: 2 occurrences replaced