POS for .NET Barcode scanner DeviceEnabled failed to set

Question

I'm currently developing a .NET 4.5.1 application that should use a barcode scanner to read 2D barcode text. For that, Microsoft POS for .NET 1.14.1 is installed and used. The barcode sanner (Intermec/Honeywell ED40) driver is correctly installed, the OPOS driver is an unmanaged OCX.

I use the typical workflow to create a scanner instance in a WinForms project:

public partial class MainForm : Form
{
  private PosExplorer _explorer;
  private Scanner     _scanner;

  public MainForm()
  {
    InitializeComponent();
  }

  protected override void OnShown(EventArgs e)
  {
    base.OnShown(e);

    _explorer = new PosExplorer(this);
    DeviceInfo  device = myPosExplorer.GetDevice(DeviceType.Scanner, "Intermec_RS-232_Scanner");
    _scanner = (Scanner)explorer.CreateInstance(device);
    _scanner.Open();
    _scanner.Claim(1000);
    _scanner.DataEvent += scanner_DataEvent;
    _scanner.ErrorEvent += scanner_ErrorEvent;
    _scanner.DeviceEnabled = true; // throws here if normal user privileges
    _scanner.DataEventEnabled = true;
    _scanner.DecodeData = true;
  }
}

Everything works fine if the application is started using administrative rights. But, if it is started using normal user rights, the scanner cannot be enabled. When executing the scanner.DeviceEnabled = true statement, the following exception is thrown:

PosControlException: Failed to set property DeviceEnabled.

The same issue occurs, if I compile and start the provided Microsoft sample "Microsoft POS Tester". But the also provided, precompiled version "C:\Program Files (x86)\Microsoft Point Of Service\SDK\Samples\Sample Application\TestApp.exe" directory works, independent from the privileges.

I did not found a solution in different forums and in the POS for .NET documentation. I did several experiments with the Internet Explorer security settings for ActiveX, same problem. I guess, it is a security setting elsewere, has anybody an idea?

Environment:

• Windows 7 Pro x64
• .NET 4.5.1

Thanks.

Edit:

After many hours, I have found the reason, it was registry virtualization. The OPOS driver (OCX) of the manufacturer tries to write to the HKLM/Software/Wow6432Node/Intermec subkey. So, that write access was virtualized to HKEY_USERS/[User SID]_Classes/VirtualStore/Machine/Software/Wow6432Node/Intermec. But the key in the virtual store was incomplete, many values were missing.

Solution:

• Delete the HKEY_USERS/[User SID]_Classes/VirtualStore/Machine/Software/Wow6432Node/Intermec key in the virtual store.
• Assign Full access permissions to the Windows Users group for the original HKLM/Software/Wow6432Node/Intermec key. So, all users access the identical registry key.

Answer 1

The problem is solved, see my edit above.