.NET Core C# Requires Chilkat v11.7.0+

Search for Text in a PDF

See more PDF Text Extraction Examples

Demonstrates the "search" operation, which finds every occurrence of a string in a PDF and returns each match with its page number and the text around it. Matching ignores case unless caseSensitive is true. .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 three-page PDF used in this example is available at search_context.pdf

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

Chilkat.JsonObject json = new Chilkat.JsonObject();
Chilkat.JsonObject jsonOut = new Chilkat.JsonObject();

//  The string to find.
json.UpdateString("query","chilkat");

//  The number of characters returned before and after each match.  The default is 40.
json.UpdateInt("context",30);

success = pdf.ExtractText("search",json,jsonOut);
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

//  "count" is the number of matches.  Each match has the page, the matched text as it appears
//  in the PDF, and the text before and after it.
Debug.WriteLine("Matches: " + Convert.ToString(jsonOut.IntOf("count")));

int i = 0;
int count_i = jsonOut.SizeOfArray("matches");
while (i < count_i) {
    jsonOut.I = i;
    Debug.WriteLine("page " + Convert.ToString(jsonOut.IntOf("matches[i].page")) + ": ..." + jsonOut.StringOf("matches[i].before") + "[" + jsonOut.StringOf("matches[i].text")
         + "]" + jsonOut.StringOf("matches[i].after") + "...");
    i = i + 1;
}

//  The search ignores case by default.  Set caseSensitive to find only the exact spelling.
json.UpdateBool("caseSensitive",true);
json.UpdateString("query","Chilkat");
success = pdf.ExtractText("search",json,jsonOut);
if (success == false) {
    Debug.WriteLine(pdf.LastErrorText);
    return;
}

Debug.WriteLine("Case-sensitive matches for Chilkat: " + Convert.ToString(jsonOut.IntOf("count")));

//  Sample output:

//  Matches: 5
//  page 1: ...[Chilkat] River Field Notes The Chilkat...
//  page 1: ...Chilkat River Field Notes The [Chilkat] River runs for about fifty mi...
//  page 2: ...DAY ONE: UPPER [CHILKAT] FLATS Clear and cold, minus e...
//  page 2: ...he river is sometimes spelled [chilkat] in older records, and the val...
//  page 3: ...y because the fish run on the [Chilkat] was thinning. Two tagged bird...
//  Case-sensitive matches for Chilkat: 3