//// This code is part of Document Solutions for PDF .NET demos.// Copyright (c) MESCIUS inc. All rights reserved.//using System.IO;using GrapeCity.Documents.Pdf;using GrapeCity.Documents.Pdf.AcroForms;
namespace DsPdfWeb.Demos{    // 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 int CreatePDF(Stream stream)        {            var doc = new GcPdfDocument();            using (var fs = File.OpenRead(Path.Combine("Resources", "PDFs", "TimeSheet.pdf")))            {                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;
                void removeSignatures(FieldCollection fields)                {                    foreach (var f in fields)                    {                        if (f is SignatureField sf)                            sf.Value = null;                        removeSignatures(f.Children);                    }                }            }        }    }}