C# Requires Chilkat v11.7.0+

Fill a PDF Template: Replace {{placeholders}} with Values

See more PDF Text Replacement Examples

Demonstrates the TextReplace method on an invoice template whose values are written as placeholders such as {{customer}} and {{total}}. The "placeholders" object names each placeholder and the text to put in; every occurrence on the page is replaced, including a placeholder inside a sentence or inside a label such as "Tax ({{taxRate}}):". The text is redrawn with the font the template used, so the result looks like the template, and a value that is right-aligned in the template stays right-aligned. The changes are written by WriteFile. 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;
}

//  The template has these placeholders in its page text:
//    {{customer}} (twice: "Bill To:" and the closing sentence), {{date}}, {{po}},
//    two item rows: {{qty1}} {{desc1}} {{price1}} {{amount1}} and {{qty2}} {{desc2}} {{price2}} {{amount2}},
//    {{subtotal}}, "Tax ({{taxRate}}):" with {{tax}}, and {{total}}.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("placeholders.customer","Acme Corp");
json.UpdateString("placeholders.date","2026-10-18");
json.UpdateString("placeholders.po","PO-88213");
json.UpdateString("placeholders.qty1","2");
json.UpdateString("placeholders.desc1","Cordless drill, 18 V");
json.UpdateString("placeholders.price1","$460.00");
json.UpdateString("placeholders.amount1","$920.00");
json.UpdateString("placeholders.qty2","6");
json.UpdateString("placeholders.desc2","Galvanized hinge, 4 inch");
json.UpdateString("placeholders.price2","$12.50");
json.UpdateString("placeholders.amount2","$75.00");
json.UpdateString("placeholders.subtotal","$995.00");
json.UpdateString("placeholders.taxRate","7.35%");
json.UpdateString("placeholders.tax","$73.13");
json.UpdateString("placeholders.total","$1,068.13");

//  "apply" makes every replacement, or none: if any value cannot be drawn with the
//  template's font, the method returns false, the PDF is unchanged, and jsonOut says why.
Chilkat.JsonObject jsonOut = new Chilkat.JsonObject();
success = pdf.TextReplace("apply",json,jsonOut);
if (success == false) {
    Debug.WriteLine("Not applied: " + jsonOut.Emit());
    if (success == false) {
        Debug.WriteLine(pdf.LastErrorText);
        return;
    }

}

//  One entry per placeholder: the pages it was found on and how many times it was replaced.
int i = 0;
int count_i = jsonOut.SizeOfArray("replacements");
while (i < count_i) {
    jsonOut.I = i;
    Debug.WriteLine(jsonOut.StringOf("replacements[i].field") + ": " + Convert.ToString(jsonOut.IntOf("replacements[i].count")) + " on page(s) " + jsonOut.StringOf("replacements[i].pages"));
    i = i + 1;
}

//  The replacements stay in memory until the PDF is written.
success = pdf.WriteFile("qa_output/invoice_filled.pdf");
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("Wrote qa_output/invoice_filled.pdf");

//  Sample output:

//  customer: 2 on page(s) 1
//  date: 1 on page(s) 1
//  po: 1 on page(s) 1
//  qty1: 1 on page(s) 1
//  desc1: 1 on page(s) 1
//  price1: 1 on page(s) 1
//  amount1: 1 on page(s) 1
//  qty2: 1 on page(s) 1
//  desc2: 1 on page(s) 1
//  price2: 1 on page(s) 1
//  amount2: 1 on page(s) 1
//  subtotal: 1 on page(s) 1
//  taxRate: 1 on page(s) 1
//  tax: 1 on page(s) 1
//  total: 1 on page(s) 1
//  Wrote qa_output/invoice_filled.pdf