Acrobat 8.1 and C# - How can you detect password protected PDF files?

Question

I am modifying our existing C# code that opens PDF files.  But when ever we hit a password protected file, we are prompted for a password.  This is an automated process, so if we detect a password protected file, we move the file to a manual processing folder to be processed later.
We are using Acrobat 8.1 Standard.
Our code looks like this:
using 
System;
using 
System.Collections.Generic;
using 
System.Linq;
using 
System.Text;
using 
Acrobat;
using 
System.IO;
using 
Word = Microsoft.Office.Interop.Word;
using 
System.Reflection;
     AcroApp app = new AcroApp();     app.Hide();
     try
          if (app != null)          {
               app.CloseAllDocs();
               AcroAVDoc av = new AcroAVDoc(); 
               if (av.Open(filename, "Test") == true)               {
                    AcroPDDoc doc = new AcroPDDoc();                    doc = (
AcroPDDoc)av.GetPDDoc(); 
                    doc.Save((
short)Acrobat.PDSaveFlags.PDSaveFull, 
                    Utilities.GeneratePath(FileVersion.TEMP) + fi.Name.RemoveFileExtension() + ".PDF");                    doc.Close();
     catch (Exception ex)     {
          ErrorLog.LogError(filename.RemoveFileExtension(), ex);     }
     finally
          app.CloseAllDocs();
          app.Exit();
This works great for non-password protected PDF files, but it prompts for a password if the file is password protected.  I was looking at the FileOpenEX functionality, but I can not find the reference to bring into my C# project.  It looks like it is only for C++, since I could only find C++ examples.
Any help would be appreciated.
Thanks,
Tom

Answer 1

There are no methods in the Acrobat SDK for C# for what you wish to accomplish.