ABCpdf .NET PDF Component Documentation - PdfValidationOperation Read Function. Read and validate an existing document.

string path = Server.MapPath("pdfa.pdf");
using (var op = new PdfValidationOperation()) {
  op.Conformance = PdfConformance.PdfA1b;
  using var doc = op.Read(path, null);

  if (op.Errors.Count > 0) {
    Console.WriteLine("Errors:");
    for (int i = 0; i < op.Errors.Count; ++i)
      Console.WriteLine(op.Errors[i]);
  }
  if (op.Warnings.Count > 0) {
    if (op.Errors.Count > 0)
      Console.WriteLine();
    Console.WriteLine("Warnings:");
    for (int i = 0; i < op.Warnings.Count; ++i)
      Console.WriteLine(op.Warnings[i]);
  }
}

Dim thePath As String = Server.MapPath("pdfa.pdf")
Using theOperation As New PdfValidationOperation()
  theOperation.Conformance = PdfConformance.PdfA1b
  Dim doc As Doc = theOperation.Read(thePath, Nothing)
  doc.Dispose()

  If theOperation.Errors.Count > 0 Then
    Console.WriteLine("Errors:")
    Dim i As Integer = 0
    While i < theOperation.Errors.Count
      Console.WriteLine(theOperation.Errors(i))
      System.Threading.Interlocked.Increment(i)
    End While
  End If
  If theOperation.Warnings.Count > 0 Then
    If theOperation.Errors.Count > 0 Then
      Console.WriteLine()
    End If
    Console.WriteLine("Warnings:")
    Dim i As Integer = 0
    While i < theOperation.Warnings.Count
      Console.WriteLine(theOperation.Warnings(i))
      System.Threading.Interlocked.Increment(i)
    End While
  End If
End Using