VB.NET 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. VB.NET

Dim success As Boolean = 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

Dim pdf As New Chilkat.Pdf
success = pdf.LoadFile("qa_data/pdf/search_context.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Dim json As New Chilkat.JsonObject
Dim jsonOut As 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) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


'  "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: " & jsonOut.IntOf("count"))

Dim i As Integer = 0
Dim count_i As Integer = jsonOut.SizeOfArray("matches")
While i < count_i
    jsonOut.I = i
    Debug.WriteLine("page " & jsonOut.IntOf("matches[i].page") & ": ..." & jsonOut.StringOf("matches[i].before") & "[" & jsonOut.StringOf("matches[i].text") & "]" _
         & jsonOut.StringOf("matches[i].after") & "...")
    i = i + 1
End While

'  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) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("Case-sensitive matches for Chilkat: " & 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