'''' This code is part of Document Solutions for PDF .NET demos.'' Copyright (c) MESCIUS inc. All rights reserved.''Imports System.IOImports GrapeCity.Documents.PdfImports GrapeCity.Documents.Pdf.AcroForms
'' This sample shows how to find and remove existing signatures'' from a PDF that had been digitally signed.'' See the RemoveSignatureFields for code that removes any'' signature fields instead.'' The PDF used in this sample was created by TimeSheet.Public Class RemoveSignatures    Public Function CreatePDF(ByVal stream As Stream) As Integer        Dim doc = New GcPdfDocument()        Using fs As New FileStream(Path.Combine("Resources", "PDFs", "TimeSheet.pdf"), FileMode.Open, FileAccess.Read)            doc.Load(fs)
            '' Fields can be children of other fields, so we use            '' a recursive method to iterate through the whole tree:            RemoveSignatures(doc.AcroForm.Fields)
            '' Done:            doc.Save(stream)            Return doc.Pages.Count        End Using    End Function
    Sub RemoveSignatures(ByVal fields As FieldCollection)        For i = fields.Count - 1 To 0 Step -1            If TypeOf fields(i) Is SignatureField Then                DirectCast(fields(i), SignatureField).Value = Nothing            End If            RemoveSignatures(fields(i).Children)        Next    End SubEnd Class