DigitalSignatureCollection Class

public class DigitalSignatureCollection : IEnumerable

Public Class DigitalSignatureCollection
	Implements IEnumerable

public ref class DigitalSignatureCollection : IEnumerable

type DigitalSignatureCollection =  
    class
        interface IEnumerable
    end

[C#]
internal void ValidateSignature()
{
   Workbook wb = new Workbook(@"c:\newfile.xlsx");
   //wb.IsDigitallySigned is true when the workbook is signed already.
   System.Console.WriteLine(wb.IsDigitallySigned);
   //get digitalSignature collection from workbook
   DigitalSignatureCollection dsc = wb.GetDigitalSignature();
   foreach (DigitalSignature ds in dsc)
   {
       System.Console.WriteLine(ds.Comments);
       System.Console.WriteLine(ds.SignTime);
       System.Console.WriteLine(ds.IsValid);
   }
}
internal void SignSignature()
{
   //dsc is signature collection contains one or more signature needed to sign
   DigitalSignatureCollection dsc = new DigitalSignatureCollection();
   //cert must contain private key, it can be contructed from cert file or windows certificate collection.
   //123456 is password of cert
   X509Certificate2 cert = new X509Certificate2("c:\\mykey2.pfx", "123456");
   DigitalSignature ds = new DigitalSignature(cert, "test for sign", DateTime.Now);
   dsc.Add(ds);
   Workbook wb = new Workbook();
   //wb.SetDigitalSignature sign all signatures in dsc
   wb.SetDigitalSignature(dsc);
   wb.Save(@"c:\newfile.xlsx");
}

[Visual Basic]
   Sub ValidateSignature()
   Dim workbook As Workbook = New Workbook("c:\newfile.xlsx")
   'Workbook.IsDigitallySigned is true when the workbook is signed already.
   System.Console.WriteLine(workbook.IsDigitallySigned)
   'get digitalSignature collection from workbook
   Dim dsc As DigitalSignatureCollection = workbook.GetDigitalSignature()
   Dim ds As DigitalSignature
   For Each ds In dsc
       System.Console.WriteLine(ds.Comments)
       System.Console.WriteLine(ds.SignTime)
       System.Console.WriteLine(ds.IsValid)
   Next
End Sub

Sub SignSignature()
   'dsc is signature collection contains one or more signature needed to sign
   Dim dsc As DigitalSignatureCollection = New DigitalSignatureCollection()
   'cert must contain private key, it can be contructed from cert file or windows certificate collection.
   Dim cert As X509Certificate2 = New X509Certificate2("c:\mykey2.pfx", "123456")
   'create a signature with certificate, sign purpose and sign time
   Dim ds As DigitalSignature = New DigitalSignature(cert, "test for sign", DateTime.Now)
   dsc.Add(ds)
   Dim workbook As Workbook = New Workbook()
   'workbook.SetDigitalSignature sign all signatures in dsc
   workbook.SetDigitalSignature(dsc)
   workbook.Save("c:\newfile.xlsx")
End Sub