C# 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. C#

bool success = 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

Chilkat.Pdf pdf = new Chilkat.Pdf();
success = pdf.LoadFile("qa_data/pdf/invoice_template.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Chilkat.JsonObject json = new Chilkat.JsonObject();
Chilkat.JsonObject jsonOut = 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) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("default: " + Convert.ToString(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) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("occurrence 2: " + Convert.ToString(jsonOut.IntOf("replacements[0].count")) + " occurrence replaced");

//  Every occurrence.
json.UpdateString("labels[0].occurrence","all");
success = pdf.TextReplace("apply",json,jsonOut);
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("occurrence all: " + Convert.ToString(jsonOut.IntOf("replacements[0].count")) + " occurrences replaced");

success = pdf.WriteFile("qa_output/invoice_refs.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

//  Sample output:

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