PdfDocumentSigner.ClearSignatureField(String) Method

Removes a signature applied to the specific signature field.

Namespace: DevExpress.Pdf

Assembly: DevExpress.Docs.v20.1.dll

NuGet Package: DevExpress.Document.Processor

NuGet Packages: DevExpress.Document.Processor, DevExpress.WindowsDesktop.Document.Processor

Declaration

C#

public void ClearSignatureField(
    string formFieldName
)

VB.NET

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#

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

//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", PdfHashAlgorithm.SHA256);

    //Retrieve all signed form fields:
    var signedFields = signer.GetSignatureNames(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";

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

VB.NET

Imports DevExpress.Pdf
Imports System.Diagnostics
Imports System.IO

'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", PdfHashAlgorithm.SHA256)

  'Retrieve all signed form fields:
  Dim signedFields = signer.GetSignatureNames(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"

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