PdfDocumentSigner.ClearSignatureField(String) Method

Removes a signature applied to the specific signature field.

Assembly : DevExpress.Docs.v25.2.dll

NuGet Package : DevExpress.Document.Processor

Declaration

C#
VB.NET

csharp

public void ClearSignatureField(
    string formFieldName
)

Public Sub ClearSignatureField(
    formFieldName As String
)

Parameters

Name	Type	Description
formFieldName	String

The field name to clear.

Remarks

The PdfDocumentSigner.GetSignatureFieldNames() allows you to retrieve signed form field names.

Use the PdfDocumentSigner.ClearSignatureFields() method to clear all signed form fields.

The code sample below shows how to retrieve signed form field names and apply a new signature to the first field:

C#
VB.NET

csharp

using DevExpress.Pdf;
using System.Diagnostics;
using System.IO;
using DevExpress.Office.DigitalSignatures;

// Load a document to sign:
using (var signer = new PdfDocumentSigner("Document.pdf"))
{
    // Create a PKCS#7 signature:
    Pkcs7Signer pkcs7Signature = new Pkcs7Signer("Signing Documents//certificate.pfx", "123", 
        HashAlgorithmType.SHA256);

    // Retrieve all signed form fields:
    var signedFields = signer.GetSignatureFieldNames(false);

    // Clear the first signature field:
    signer.ClearSignatureField(signedFields[0]);

    // Apply a new signature to this form field:
    var santuzzaSignature = new PdfSignatureBuilder(pkcs7Signature, signedFields[0]);

    // Specify image and signer information:
    santuzzaSignature.SetImageData(File.ReadAllBytes("Signing Documents//SantuzzaValentina.jpg"));
    santuzzaSignature.Location = "Australia";
    santuzzaSignature.Name = "Santuzza Valentina";
    santuzzaSignature.Reason = "I Agree";
    santuzzaSignature.CertificationLevel = PdfCertificationLevel.FillFormsAndAnnotate;

    // Sign and save the document:
    signer.SaveDocument("SignedDocument.pdf", santuzzaSignature);
}

Imports DevExpress.Pdf
Imports System.Diagnostics
Imports System.IO
Imports DevExpress.Office.DigitalSignatures

' Load a document to sign:
Using signer = New PdfDocumentSigner("Document.pdf")
  ' Create a PKCS#7 signature:
  Dim pkcs7Signature As New Pkcs7Signer("Signing Documents//certificate.pfx", "123", 
                                        HashAlgorithmType.SHA256)

  ' Retrieve all signed form fields:
  Dim signedFields = signer.GetSignatureFieldNames(False)

  ' Clear the first signature field:
  signer.ClearSignatureField(signedFields(0))

  ' Apply a new signature to this form field:
  Dim santuzzaSignature = New PdfSignatureBuilder(pkcs7Signature, signedFields(0))

  ' Specify image and signer information:
  santuzzaSignature.SetImageData(File.ReadAllBytes("Signing Documents//SantuzzaValentina.jpg"))
  santuzzaSignature.Location = "Australia"
  santuzzaSignature.Name = "Santuzza Valentina"
  santuzzaSignature.Reason = "I Agree"
  santuzzaSignature.CertificationLevel = PdfCertificationLevel.FillFormsAndAnnotate

  ' Sign and save the document:
  signer.SaveDocument("SignedDocument.pdf", santuzzaSignature)
End Using