Pdf VB.NET WinRT Reference Documentation

Pdf

Current Version: 9.5.0.90

A PDF class for various tasks such as signature verification, signing, encrypt, decrypt, etc.

Object Creation

Dim obj As New Chilkat.Pdf()

Properties

DebugLogFilePath
DebugLogFilePath As String

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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LastErrorHtml
LastErrorHtml As String (ReadOnly)

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
LastErrorText As String (ReadOnly)

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
LastErrorXml As String (ReadOnly)

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
LastMethodSuccess As Boolean
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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NumPages
NumPages As Integer (ReadOnly)
Introduced in version 9.5.0.85

The number of pages in the currently open PDF.

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NumSignatures
NumSignatures As Integer (ReadOnly)
Introduced in version 9.5.0.85

The number of digital signatures present in the currently open PDF.

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UncommonOptions
UncommonOptions As String
Introduced in version 9.5.0.85

This is a catch-all property to be used for uncommon needs. This property defaults to the empty string. It can be set to a list of one or more of the following comma separated keywords:

  • "WriteStandardXref" - When writing the PDF, write the cross reference section in standard format if possible. (The "standard format" is the older non-compressed format.)
  • "NO_VERIFY_CERT_SIGNATURES" - When countersigning a PDF (i.e. adding a new signature to a PDF that already contains one or more signatures), Chilkat will automatically validate the existing signatures and their certificates. (The signing certificates are typically embedded within a signature.) If any of these validations fail, the new signature is not added. Sometimes, an existing signature is validated, but the certs in the chain of authentication, such as issuer certs or root CA certs, are not included and not available to check. In this case, you can add the "NO_VERIFY_CERT_SIGNATURES" to skip the existing signature certificate validations.

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VerboseLogging
VerboseLogging As Boolean

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Version As String (ReadOnly)

Version of the component/library, such as "9.5.0.63"

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Methods

AddSigningCert
Function AddSigningCert(ByVal cert As Cert) As Boolean
Introduced in version 9.5.0.85

Adds a certificate to be used for PDF signing. To sign with more than one certificate, call AddSigningCert once per certificate.

Note: This method is used to provide the ability to sign once with multiple certificates. This is different than signing with one certificate, and then signing again with a different certificate.

Returns True for success, False for failure.

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GetDss
Function GetDss(ByVal json As JsonObject) As Boolean
Introduced in version 9.5.0.85

Gets the contents of the PDF's Document Security Store (/DSS) if it exists. Returns the information in JSON format (in json). If there is no /DSS then an empty JSON document "{}" is returned in json.

Returns True for success, False for failure.

More Information and Examples
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GetSignerCert
Function GetSignerCert(ByVal index As Integer, ByVal cert As Cert) As Boolean
Introduced in version 9.5.0.87

This method can be used to get the signer certificate after calling VerifySignature. The index should be the same value as the index passed to VerifySignature. If successful, and if the signer certificate is fully available within the signature, the cert is loaded with the signer certificate.

Returns True for success, False for failure.

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GetUnsignedSigFields
Function GetUnsignedSigFields(ByVal json As JsonObject) As Boolean
Introduced in version 9.5.0.90

Returns JSON containing the name of each unsigned signature field found in the PDF.

Returns True for success, False for failure.

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LastJsonData
Function LastJsonData() As JsonObject
Introduced in version 9.5.0.88

Provides information about what transpired in the last method called. For many methods, there is no information. For some methods, details about what transpired can be obtained via LastJsonData. For example, after calling a method to verify a signature, the LastJsonData will return JSON with details about the algorithms used for signature verification.

Returns Nothing on failure

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LoadBd
Function LoadBd(ByVal pdfData As BinData) As Boolean
Introduced in version 9.5.0.85

Loads the PDF file contained in pdfData.

Returns True for success, False for failure.

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LoadFile
Function LoadFile(ByVal filePath As String) As Boolean
Introduced in version 9.5.0.85

Load a PDF file into this object in memory.

Returns True for success, False for failure.

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SetHttpObj
Sub SetHttpObj(ByVal http As Http)
Introduced in version 9.5.0.85

Sets the HTTP object to be used to communicate with the timestamp authority (TSA) server for cases where long term validation (LTV) of signatures is desired. The http is used to send the requests, and it allows for connection related settings and timeouts to be set. For example, if HTTP or SOCKS proxies are required, these features can be specified on the http.

The http is also used to send OCSP requests to store OCSP responses in the PDF's document security store (DSS).

Returns True for success, False for failure.

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SetSignatureJpeg
Function SetSignatureJpeg(ByVal jpgData As BinData) As Boolean
Introduced in version 9.5.0.85

Provides an optional JPG image to be included in the signature appearance. The JPG data is passed in jpgData.

Note: JPG images must use the BaseLine format and not the Progressive format. (Programs typically save JPEG's using the BaseLine format as default.)

Returns True for success, False for failure.

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SetSigningCert
Function SetSigningCert(ByVal cert As Cert) As Boolean
Introduced in version 9.5.0.85

Specifies a certificate to be used when signing the PDF. Signing requires both a certificate and private key. In this case, the private key is implicitly specified if the certificate originated from a PFX that contains the corresponding private key, or if on a Windows-based computer where the certificate and corresponding private key are pre-installed.

Returns True for success, False for failure.

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SetSigningCert2
Function SetSigningCert2(ByVal cert As Cert, ByVal privateKey As PrivateKey) As Boolean
Introduced in version 9.5.0.85

Specifies a digital certificate and private key to be used for signing the PDF.

Returns True for success, False for failure.

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SignPdf
<Awaitable> Function SignPdfAsyncAsync(ByVal jsonOptions As JsonObject, ByVal outFilePath As String) As IAsyncOperation(Of Boolean)
Introduced in version 9.5.0.85

Signs the open PDF and if successful writes the signed PDF to the ARG3. The jsonOptions contains information and instructions about the signature. See the examples below for more detailed information about the JSON options listed here.

Summary of PDF Signing Options

  • appearance.fillUnsignedSignatureField - Can be set to true) to tell Chilkat to sign an existing unsigned signature field. Chilkat will automatically scale the visual appearance (text + graphics) to fit the pre-existing signature field. When fillUnsignedSignatureField is specified, it is not necessary to set appearance.x, appearance.y, appearance.fontScale, etc. Starting in v9.5.0.90, the unsignedSignatureField option (see below) can be used to specify the unsigned signature field to be used. Otherwise, the 1st available unsigned field is used.
  • appearance.fontScale - The font scale (in pts) to be used, such as "10.0".
  • appearance.height - Optional to specify the exact height of the visible signature rectangle in points, where 72 points equals 1 inch. If the appearance.height is set, then appearance.width should be set to "auto" (or left unset). Chilkat will compute the font scale to achieve the desired rectangle height, and the resulting width will depend on the text.
  • appearance.image - Indicates an image will be included in the signature. Set to the keyword "custom-jpg" to use an image set by calling the SetSignatureJpeg method. Otherwise can be set to one of the following keywords to indicate a built-in SVG graphic. (These are graphics embedded within the Chilkat library itself.)
    • green-check-grey-circle
    • green-check-green-circle
    • application-approved
    • application-rejected
    • document-accepted
    • approved
    • blue-check-mark
    • green-check-mark
    • green-check-grey-circle
    • red-x-red-circle
    • rejected
    • result-failure
    • result-pass
    • signature
    • document-check
    • document-x
    • red-x-grey-circle
  • appearance.imageOpacity - Sets the image opacity. Can be an integer from 1 to 100.
  • appearance.imagePlacement - Sets the image placment within the signature rectangle. Can be "left", "right", or "center". Images placed in the center typically have opacity 50% or less because the text is displayed over the image (i.e. it is a background image). Images placed left or right are not background images. The signature rectangle is divided into two sub-rectangles, one for the image, and one for the text.
  • appearance.margin_x - If the appearance.x is set to "left", then this can optionally be use to specify the position from the left edge. The default margin is 10.0 (10 points, where 72 points equals 1 inch).
  • appearance.margin_y - If the appearance.y is set to "top", then this can optionally be use to specify the position from the top. The default margin for y is 20.0 (20 points, where 72 points equals 1 inch).
  • appearance.text[i] - The text that should appear in the signature box. Each line is specified in a JSON array item, where "i" is an integer starting with "0" as the 1st line. The text can contain the following keywords which are replaced with actual values:
    • cert_country - The signing certificate's subject country (C).
    • cert_cn - The signing certificate's subject common name (CN).
    • cert_dn - The signing certificate's DN (distinguished name).
    • cert_email - The signing certificate's subject email address (E).
    • cert_issuer_cn - The signing certificate's issuer's common name (CN).
    • cert_locality - The signing certificate's subject locality (L).
    • cert_organization - The signing certificate's subject organization (O).
    • cert_org_id - The signing certificate's organization ID.
    • cert_ou - The signing certificate's subject organizational unit (OU).
    • cert_san_rfc822name - The signing certificate's RFC822 subject alternative name.
    • cert_serial_dec - The signing certificate's serial number in decimal format.
    • cert_serial_hex - The signing certificate's serial number in hex format.
    • cert_state - The signing certificate's subject state (S).
    • cert_thumbprint - The signing certificate's thumbprint (The SHA1 hash of the binary DER representation in hex format).
    • current_datetime - Current local date/time in the format such as "Sep 11 2020 16:30:54".
    • current_dt - Current local date/time in PDF date/time string format, such as YYYY.MM.DD hh:mm:ss -05'00'.
    • current_rfc822_dt_gmt - Current GMT date/time in RFC822 format, such as "Mon, 22 Nov 2021 15:58:41 GMT".
    • current_rfc822_dt_local - Current local date/time in RFC822 format, such as "Mon, 22 Nov 2021 09:56:16 -0600".
    • current_timestamp_gmt - Current GMT date/time in timestamp format, such as "1990-12-31T23:59:60Z".
    • current_timestamp_local - Current local date/time in timestamp format, such as "2019-10-12T03:20:50.52-04:00".
  • appearance.width - Optional to specify the exact width of the visible signature rectangle in points, where 72 points equals 1 inch. If the appearance.width is set, then appearance.height should be set to "auto" (or left unset). Chilkat will compute the font scale to achieve the desired rectangle width, and the resulting height will depend on the text and number of lines of text.
  • appearance.x - The horizontal position on the page of the left edge of the signature box. Can be a keyword such as "left", "right", or "middle" to specify a typical placement with default margins. Otherwise can be a floating point number where 0.0 is the leftmost coordinate of a page, and 612.0 is the right most. Can also be the keyword "after" to place the signature just to the right of the rightmost signature on the page.
  • appearance.y - The vertical position on the page of the top edge of the signature box. Can be one of the keywords "top" or "bottom" to specify a typical placement with default margins. Otherwise can be a floating point number where 0.0 is the bottom coordinate of a page, and 792.0 is the top. Can also be the keyword "under" to place the signature just under the bottommost signature on the page.
  • contactInfo - Optional to provide free-form text with contact information about the signer.
  • docMDP.add - Set this boolean value to true to include the Document MDP Permissions with a certifying signature. When a certifying signature is desired, both "lockAfterSigning" and "docMDP.add" should be specified. The default Doc MDP permission level is 2.
  • docMDP.accessPermissions - Include this if the docMDP.add is specified, and a permission level different from the default value of 2 is desired. Possible values are:
    • 1: No changes to the document are permitted and any changes invalidate the signature.
    • 2: Permitted changes include filling in forms, instantiating page templates and signing.
    • 3: Same as 2, but also allow annotation creation, deletion, and modification.
  • embedCertChain - Boolean to control whether the certificate chain is included in the signature. The default is to include the certificates in the chain of authentication. Set this to false to only include the signing certificate (this is not common).
  • hashAlgorithm - If the signing certificate is RSA-based, and the signing scheme (padding scheme) is RSA-PSS, then this specifies the PSS hash algorithm. Can be "sha1", "sha256", "sha384", or "sha512". ("sha256" is what should be commonly chosen.)
  • includeRootCert - Boolean to control whether the root CA certificate is included in the certificate chain (assuming the certificate chain is included). The default is to include the root CA certificate. Set this to false to exclude the root CA certificate from being included (this is not common).
  • info.* - (added in Chilkat v9.5.0.90) Provides the ability to add or update the PDF document's "/Info", such as "Creator", "Producer", "Title", etc. Any number of arbitrary member names can be specified and these will be added to the document's /Info dictionary. However, Chilkat will ignore "ModDate" and "CreationDate" because ModDate is automatically set to the current system date/time and the CreationDate should not change.
  • invisibleSignature - Set this boolean to true to create an invisible signature with no appearance.
  • legalAttestation - Set to provide a free-form text legal attestation.
  • location - Optional to provide free-form text with a description of the geographic location where the PDF was signed.
  • lockAfterSigning - Set this boolean to true to certify and lock a PDF as opposed to adding an approval signature (the default) which allows for additional countersignatures.
  • ltvOcsp - Set this boolean to true to create an LTV-enabled signature.
  • page - The page number where the signature will be placed. Page 1 is the 1st page.
  • reason - Optional to provide text indicating the reason for the signature.
  • signatureAlgorithm - If the signing certificate is RSA-based, then chooses the RSA padding scheme. Possible values are "pkcs" for PKCS-v1_5 or "pss" for RSASSA-PSS.
  • signingCertificateV2 - Set to "1" to include the "SigningCertificateV2" authenticated attribute. This is desired in most cases.
  • signingTime - Set to "1" to include the "SigningTime" authenticated attribute. This is desired in most cases. Note: This is not the same as time-stamping. This is a fundamental authenticated attribute that should be included with or without the addition of time-stamping.
  • sigTextLabel - Set to provide free-form text for the signatures annotation text label.
  • timestampToken.enabled - Set to true to tell Chilkat to request a timestamp from a TSA server and include the timestamp token in the signature's authentication attributes
  • timestampToken.tsaUrl - The timestamp server's URL.
  • timestampToken.tsaUsername, timestampToken.tsaPassword - If the timestamp server requires a login and password.
  • timestampToken.requestTsaCert - Set to true to ask the timestamp server to include its certificate in the timestamp token.
  • unsignedSignatureField - (added in Chilkat v9.5.0.90) Can be set to specify the name of the unsigned signature field that is to be signed.

Returns True for success, False for failure.

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VerifySignature
Function VerifySignature(ByVal index As Integer, ByVal sigInfo As JsonObject) As Boolean
Introduced in version 9.5.0.85

Verifies the Nth signature contained in the PDF, where the 1st signature is indicated by an index of 0. Returns True if the signature valid, otherwise returns False. The sigInfo is an output argument and is populated with information about the validated or unvalidated signature.

Returns True for success, False for failure.

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Events