Follow the steps to achieve the desired result.
Complete code
using System;
using System.IO;
using SautinSoft;
using SautinSoft.Pdf;
using SautinSoft.Pdf.Content;
using SautinSoft.Pdf.Forms;
namespace Sample
{
class Sample
{
/// <summary>
/// How to determine the signing date of a digital signature on a current pdf using C# and .NET
/// </summary>
/// <remarks>
/// Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/determine-the-signing-date-of-a-digital-signature-on-a-current-pdf-csharp-dotnet.php
/// </remarks>
static void Main(string[] args)
{
// Before starting this example, please get a free 100-day trial key:
// https://sautinsoft.com/start-for-free/
// Apply the key here:
// PdfDocument.SetLicense("...");
string inpFile = Path.GetFullPath(@"..\..\..\digital signature.pdf");
using (PdfDocument document = PdfDocument.Load(inpFile))
{
var field = document.Form.Fields.FirstOrDefault(f => f is PdfSignatureField);
if (field != null && field is PdfSignatureField signField)
{
Console.WriteLine($"The signature date is {signField.Value.Date}.");
}
else
{
Console.WriteLine("The PDF doesn't have a digital signature!");
}
}
}
}
}
Option Infer On
Imports System
Imports System.IO
Imports SautinSoft
Imports SautinSoft.Pdf
Imports SautinSoft.Pdf.Content
Imports SautinSoft.Pdf.Forms
Namespace Sample
Friend Class Sample
''' <summary>
''' How to determine the signing date of a digital signature on a current pdf using C# and .NET
''' </summary>
''' <remarks>
''' Details: https://sautinsoft.com/products/pdf/help/net/developer-guide/determine-the-signing-date-of-a-digital-signature-on-a-current-pdf-csharp-dotnet.php
''' </remarks>
Shared Sub Main(ByVal args() As String)
' Before starting this example, please get a free 100-day trial key:
' https://sautinsoft.com/start-for-free/
' Apply the key here:
' PdfDocument.SetLicense("...");
Dim inpFile As String = Path.GetFullPath("..\..\..\digital signature.pdf")
Using document As PdfDocument = PdfDocument.Load(inpFile)
Dim field = document.Form.Fields.FirstOrDefault(Function(f) TypeOf f Is PdfSignatureField)
Dim tempVar As Boolean = TypeOf field Is PdfSignatureField
Dim signField As PdfSignatureField = If(tempVar, CType(field, PdfSignatureField), Nothing)
If field IsNot Nothing AndAlso tempVar Then
Console.WriteLine($"The signature date is {signField.Value.Date}.")
Else
Console.WriteLine("The PDF doesn't have a digital signature!")
End If
End Using
End Sub
End Class
End Namespace
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