private void btnCreateAndSign_Click(object sender, EventArgs e)
{
//Load the Excel file.
if (OpenExcelDialog.ShowDialog() != DialogResult.OK)
{
return;
}
XlsFile xls = new XlsFile();
xls.Open(OpenExcelDialog.FileName);
string DataPath = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location) + @"\..\..\";
//Export it to pdf.
using (FlexCelPdfExport pdf = new FlexCelPdfExport(xls, true))
{
pdf.FontEmbed = TFontEmbed.Embed;
//Load the certificate and create a signer.
//In this example we just have the password in clear. It should be kept in a SecureString.
//Also make sure to set the flag X509KeyStorageFlags.EphemeralKeySet to avoid files created
//on disk: https://snede.net/the-most-dangerous-constructor-in-net/
//As X509KeyStorageFlags.EphemeralKeySet only exists in .NET 4.8 or newer, for older versions we will
//define it as (X509KeyStorageFlags)32. For .NET 4.8 or newer and NET Core, you can use X509KeyStorageFlags.EphemeralKeySet
X509Certificate2 Cert = new X509Certificate2(DataPath + "flexcel.pfx", "password", X509KeyStorageFlags.EphemeralKeySet);
//Note that to use the CmsSigner class you need to add a reference to System.Security dll.
//It is *not* enough to add it to the using clauses, you need to add a reference to the dll.
CmsSigner Signer = new CmsSigner(Cert);
//By default CmsSigner uses SHA1, but SHA1 has known vulnerabilities and it is deprecated.
//So we will use SHA512 instead.
//"2.16.840.1.101.3.4.2.3" is the Oid for SHA512.
Signer.DigestAlgorithm = new System.Security.Cryptography.Oid("2.16.840.1.101.3.4.2.3");
TPdfSignature sig;
if (cbVisibleSignature.Checked)
{
using (MemoryStream fs = new MemoryStream())
{
SignaturePicture.Image.Save(fs, ImageFormat.Png);
byte[] ImgData = fs.ToArray();
//The -1 as "page" parameter means the last page.
sig = new TPdfVisibleSignature(new TBuiltInSignerFactory(Signer),
"Signature", "I have read the document and certify it is valid.", "Springfield", "*****@*****.**", -1, new RectangleF(50, 50, 140, 70), ImgData);
}
}
else
{
sig = new TPdfSignature(new TBuiltInSignerFactory(Signer),
"Signature", "I have read the document and certify it is valid.", "Springfield", "*****@*****.**");
}
//You must sign the document *BEFORE* starting to write it.
pdf.Sign(sig);
if (savePdfDialog.ShowDialog() != DialogResult.OK)
{
return;
}
using (FileStream PdfStream = new FileStream(savePdfDialog.FileName, FileMode.Create))
{
pdf.BeginExport(PdfStream);
pdf.ExportAllVisibleSheets(false, "Signed Pdf");
pdf.EndExport();
}
}
if (MessageBox.Show("Do you want to open the generated file?", "Confirm", MessageBoxButtons.YesNo, MessageBoxIcon.Question) != DialogResult.Yes)
{
return;
}
Process.Start(savePdfDialog.FileName);
}