(VB.NET) Verify XAdES with External File Reference

Demonstrates how to validate an XML digital signature that contains a reference to an external file. (This is one way of doing it..)

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' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' Load the XAdES file to be validated..
Dim sbXml As New Chilkat.StringBuilder
Dim success As Boolean = sbXml.LoadFile("qa_data/xml_dsig_valid_samples/externalFile/test.pdf.XAdES","utf-8")
If (success = False) Then
    Debug.WriteLine("Failed to load XAdES input file.")
    Exit Sub
End If


Dim validator As New Chilkat.XmlDSig

' Specify a set of absolute or relative directory paths to be searched for any external file references.
' Directory paths are separated by semicolon chars.
validator.ExternalRefDirs = "qa_data/externalFiles;qa_data/xml_dsig_valid_samples/externalFile;c:/someOtherDir"

success = validator.LoadSignatureSb(sbXml)
If (success = False) Then
    Debug.WriteLine(validator.LastErrorText)
    Exit Sub
End If


' Validate signatures as usual..
Dim i As Integer = 0
While i < validator.NumSignatures
    validator.Selector = i

    Dim valid As Boolean = validator.VerifySignature(True)
    Debug.WriteLine("Signature " & (i + 1) & " and all reference digests OK = " & valid)

    i = i + 1
End While