Visual Basic 6.0 Requires Chilkat v11.7.0+

Check a PDF Text Replacement Before Applying It

See more PDF Text Replacement Examples

Demonstrates the "check" operation, which finds every placeholder and label and applies the font rule but changes nothing, and how to read its report: "ok" says whether "apply" would succeed, "replacements" lists what would be replaced, and "problems" lists what prevents it, each with a reason. Here the first check fails because a placeholder on the page was given no value; the value is added and the check passes, and only then is "apply" called. Visual Basic 6.0

Dim success As Long
success = 0

'  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 ChilkatPdf
success = pdf.LoadFile("qa_data/pdf/invoice_template.pdf")
If (success = 0) Then
    Debug.Print pdf.LastErrorText
    Exit Sub
End If

'  Values for most of the template's placeholders -- but not {{po}}, {{qty2}}, {{desc2}}, {{price2}} or {{amount2}}.
Dim json As New ChilkatJsonObject
success = json.UpdateString("placeholders.customer","Acme Corp")
success = json.UpdateString("placeholders.date","2026-10-18")
success = json.UpdateString("placeholders.qty1","2")
success = json.UpdateString("placeholders.desc1","Cordless drill, 18 V")
success = json.UpdateString("placeholders.price1","$460.00")
success = json.UpdateString("placeholders.amount1","$920.00")
success = json.UpdateString("placeholders.subtotal","$920.00")
success = json.UpdateString("placeholders.taxRate","7.35%")
success = json.UpdateString("placeholders.tax","$67.62")
success = json.UpdateString("placeholders.total","$987.62")

'  "check" reports what "apply" would do, without changing the PDF.
Dim jsonOut As New ChilkatJsonObject
success = pdf.TextReplace("check",json,jsonOut)
If (success = 0) Then
    Debug.Print pdf.LastErrorText
    Exit Sub
End If

Debug.Print "ok: " & jsonOut.BoolOf("ok")
Debug.Print "would replace: " & jsonOut.SizeOfArray("replacements") & " placeholders"

'  Each problem names the placeholder (field) or label, and a reason:
'    notFound - the placeholder or label is not on the selected pages
'    unusedPlaceholder - a placeholder on the page was given no value
'    missingGlyph, notInEncoding, nonStandardUnembeddedFont, unsupportedFont - the font rule
'    placeholderSpansFonts - the text is drawn with more than one font or size
Dim i As Long
i = 0
Dim count_i As Long
count_i = jsonOut.SizeOfArray("problems")
Do While i < count_i
    jsonOut.I = i
    Debug.Print "problem: " & jsonOut.StringOf("problems[i].field") & jsonOut.StringOf("problems[i].label") & " - " & jsonOut.StringOf("problems[i].reason") & " (page " _
         & jsonOut.IntOf("problems[i].page") & ")"
    i = i + 1
Loop

'  Give the missing placeholders their values and check again.
success = json.UpdateString("placeholders.po","PO-88213")
success = json.UpdateString("placeholders.qty2","0")
success = json.UpdateString("placeholders.desc2","(no second item)")
success = json.UpdateString("placeholders.price2","")
success = json.UpdateString("placeholders.amount2","")
success = pdf.TextReplace("check",json,jsonOut)
If (success = 0) Then
    Debug.Print pdf.LastErrorText
    Exit Sub
End If

Debug.Print "ok after adding the values: " & jsonOut.BoolOf("ok")

'  Now apply.
If (jsonOut.BoolOf("ok") = 1) Then
    success = pdf.TextReplace("apply",json,jsonOut)
    If (success = 0) Then
        Debug.Print pdf.LastErrorText
        Exit Sub
    End If

    Debug.Print "applied: " & jsonOut.BoolOf("applied")
    success = pdf.WriteFile("qa_output/invoice_checked.pdf")
    If (success = 0) Then
        Debug.Print pdf.LastErrorText
        Exit Sub
    End If

End If

'  Sample output:

'  ok: false
'  would replace: 10 placeholders
'  problem: po - unusedPlaceholder (page 1)
'  problem: qty2 - unusedPlaceholder (page 1)
'  problem: desc2 - unusedPlaceholder (page 1)
'  problem: price2 - unusedPlaceholder (page 1)
'  problem: amount2 - unusedPlaceholder (page 1)
'  ok after adding the values: true
'  applied: true