.NET Core C# Requires Chilkat v11.7.0+

Replace the Value After a Label in a PDF (Re-issue an Invoice)

See more PDF Text Replacement Examples

Demonstrates replacing the values that follow labels such as "Invoice Number:" on a PDF that has no placeholders -- an ordinary invoice. Each entry of the "labels" array names a label as it appears on the page and the new value; the value replaces the rest of the label's line. Label matching ignores case, extra spaces and a trailing colon. The replaced text is read back with ExtractText to confirm it. .NET Core 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_labels.pdf

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

//  The invoice has lines such as "Invoice Number:   INV-2026-0412" and "Total Due:  $1,234.53".
//  Each label's new value replaces whatever follows the label on its line.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("labels[0].label","Invoice Number:");
json.UpdateString("labels[0].value","INV-2026-0500");
json.UpdateString("labels[1].label","Invoice Date:");
json.UpdateString("labels[1].value","April 2, 2026");
json.UpdateString("labels[2].label","customer");
json.UpdateString("labels[2].value","Contoso Ltd");
json.UpdateString("labels[3].label","Total Due:");
json.UpdateString("labels[3].value","$1,999.99");

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;
    }

}

int i = 0;
int count_i = jsonOut.SizeOfArray("replacements");
while (i < count_i) {
    jsonOut.I = i;
    Debug.WriteLine("Replaced the value of \"" + jsonOut.StringOf("replacements[i].label") + "\" on page " + jsonOut.StringOf("replacements[i].pages"));
    i = i + 1;
}

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

//  Read the new values back with ExtractText's label option.
Chilkat.JsonObject jsonRead = new Chilkat.JsonObject();
Chilkat.JsonObject jsonText = new Chilkat.JsonObject();
jsonRead.UpdateString("label","Total Due");
jsonRead.UpdateString("labelValue","right");
success = pdf.ExtractText("text",jsonRead,jsonText);
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("Total Due is now: " + jsonText.StringOf("text"));

//  Sample output:

//  Replaced the value of "Invoice Number:" on page 1
//  Replaced the value of "Invoice Date:" on page 1
//  Replaced the value of "customer" on page 1
//  Replaced the value of "Total Due:" on page 1
//  Total Due is now: $1,999.99