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Signing existing signature field just shows white

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Create virtual file systems and disks, expose and manage remote data as if they were files on the local disk.
Posted: 07/16/2012 07:54:17
by John Cockrell (Basic support level)
Joined: 07/16/2012
Posts: 5


I am working with the PdfBlackBox sample from
I have adjusted it to apply the signature to an existing signature field by changing
int index = Document.AddSignature();
int index = Document.AddSignature(0);
and then sending the program a pdf with signature fields in

Although when not adding the signature to an existing signature field the signature shows nicely at the top right, when adding it to an existing signature field (after the change) I just get a white box and no information. White is different, so a change has been applied, and clicking the box comes up with the signature details (reason etc). It is just the appearance isn't there.
Any idea what I am doing wrongand how i get the details to appear in the existing signature field? I have included the relevant code below.

            int index = Document.AddSignature(0);
            TElPDFSignature Sig = Document.get_Signatures(index);
            Sig.Handler = PublicKeyHandler;
            Sig.AuthorName = "John";
            Sig.SigningTime = DateTime.Now.ToUniversalTime();
            Sig.Reason ="Because";
            Sig.Invisible = false;
            Sig.SignatureType = SBPDF.Unit.stDocument;
            Sig.WidgetProps.AutoText = true;
            Sig.Invisible = false;
            Sig.WidgetProps.NoView = false;
            // adding certificate to certificate storage
            PublicKeyHandler.SignatureType = SBPDFSecurity.TSBPDFPublicKeySignatureType.pstPKCS7SHA1;
            CertStorage.Add(FCert, true);
            PublicKeyHandler.CertStorage = CertStorage;
            PublicKeyHandler.CustomName = "Adobe.PPKMS";

            // configuring timestamping settings
            if (cbTimestamp.Checked)
                TSPClient.HTTPClient = HTTPClient;
                TSPClient.HashAlgorithm = SBConstants.Unit.SB_ALGORITHM_DGST_SHA1;
                TSPClient.URL = tbTimestampServer.Text;
                PublicKeyHandler.TSPClient = TSPClient;

Posted: 07/16/2012 08:08:24
by Vsevolod Ievgiienko (EldoS Corp.)

Thank you for contacting us.

Try to set TElPDFSignature.IgnoreExistingAppearance to 'true' and check if this solves the problem.
Posted: 07/16/2012 08:16:49
by John Cockrell (Basic support level)
Joined: 07/16/2012
Posts: 5

Great! A lovely simple quick fix, thankyou for your help.



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