To anyone looking at this for a solution to errors at .open() using pos for .net with the Symbol LS2208 (or others maybe) for the error Microsoft.PointOfService.PosControlException: Method Open threw an exception. Could not read the device name
key's default value, or could not convert the Programmatic ID it holds into a valid Class ID"
it doesn't work, neither does changing permissions, making it full trust, installation orders, installation of ccos, etc etc. Motorola claim the OPOS driver you install with the sdk custom settings works. Trust me don't call or email their support, they
even accused me of not even owning the scanner and not helping until I entered my serial number (even though the form didn't require it), and took forever to get to someone at symbol division who actually had a relevant discussion. Anyway, I think the issue
seems to be that Opos .Open() method takes the "DeviceName" as a parameter where the Pos for .net open() method expects the service object to set this. Since pos for .net has legacy support, Motorola isn't updating to specifically support it, although
I think they tried because in the latest installation they added "DeviceNameOveride" to the registry key for SYMBOL_SCANNER, which doesn't work because STIOPOS.DLL needs to be fixed. The registry values do actually convert properly between CLSID and ProgID,
and are fine, changing them doesn't make a difference, and using the exact same code but for a printer with known Pos for .net support works fine. Setting a DeviceName in registry is ignored too, I think what's happening is it's searching for the device
name parameter first, which is nothing, and attempting to open it from the registry, probably from a string they build appending the device name to OLEforRetail\ServiceOPOS\Scanner, and it's failing, and it takes a while before that thread is available, (also
noticed the ThreadingModel isn't set for InProcServer32 ?). If this is the case, they should make it search for SYMBOL_SCANNER first and attempt to open it and then set the device name to it.
I have found a solution for now, though it's really bad practice, and I hate it. Spam the scanner activation in a try/catch loop. It's bad, but it works, sometimes after a few errors, sometimes after 50+, but once the scanner is opened it works perfectly
from then on, and on Win7 64bit (targeting x86) or 32bit forms or wpf and targetting .net 4.0.
This is a super simple version of how you do it.
1) Create a new forms or wpf app targeting .net 4.0
2) Change the build target from ANY CPU to x86.
3) Add a reference to Microsoft.PointOfService.dll in Microsoft Point Of Service\SDK\
4) Add a new application configuration file to project and name it App.config
5) Change the contents of App.Config to the following
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<runtime>
<NetFx40_LegacySecurityPolicy enabled="true"/>
</runtime>
</configuration>
6) This is some exremely basic code for how to do it. Since a logical name is not set by Motorola, we will use the GetDevices method instead of get device.
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.PointOfService;
namespace Symbol_Scanner
{
public partial class Form1 : Form
{
private PosExplorer _explorer;
private Scanner _curScanner;
private DeviceInfo _devScanner;
public Form1()
{
InitializeComponent();
InitExplorer();
}
private void InitExplorer()
{
_explorer = new PosExplorer();
foreach (var scanner in _explorer.GetDevices(DeviceType.Scanner).Cast<DeviceInfo>().Where(scanner => scanner.ServiceObjectName == "SYMBOL_SCANNER"))
{
_devScanner = scanner;
ActivateScanner();
}
}
private void ActivateScanner()
{
try
{
if (_devScanner == null || _devScanner.IsDeviceInfoOf(_curScanner))
return;
DeactivateScanner();
_curScanner = (Scanner)_explorer.CreateInstance(_devScanner);
_curScanner.Open();
_curScanner.Claim(1000);
_curScanner.DeviceEnabled = true;
_curScanner.DataEvent += ActiveScannerDataEvent;
_curScanner.ErrorEvent += ActiveScannerErrorEvent;
_curScanner.DecodeData = true;
_curScanner.DataEventEnabled = true;
MessageBox.Show("Scanner Activated");
}
catch (PosControlException ex)
{
// log ex here it will be error code 303
_curScanner = null;
ActivateScanner(); // this is the spam
}
}
private void DeactivateScanner()
{
if (_curScanner == null)
return;
_curScanner.Close();
_curScanner = null;
}
private void ActiveScannerDataEvent(object sender, DataEventArgs e)
{
try
{
var encoder = new ASCIIEncoding();
var scandata = encoder.GetString(_curScanner.ScanDataLabel);
MessageBox.Show(scandata);
_curScanner.DataEventEnabled = true;
}
catch (PosControlException ex)
{
MessageBox.Show(ex.ToString());
}
}
private void ActiveScannerErrorEvent(object sender, DeviceErrorEventArgs e)
{
try
{
_curScanner.DataEventEnabled = true;
}
catch (PosControlException ex)
{
MessageBox.Show(ex.ToString());
}
}
}
}
This should activate after a second and then when you scan a barcode it will show up in a mesage box. To add a logical name to the registry open up regedit and go to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\OLEforRetail\ServiceOPOS\Scanner (64bit) or HKEY_LOCAL_MACHINE\SOFTWARE\OLEforRetail\ServiceOPOS\Scanner
(32bit) and add a new string value with the name of your device as the name, and the value also as the name. So for instance,
"SYMBOL_SCANNER" as name and "SYMBOL_SCANNER" as value. Then you can use _explorer.GetDevice(Scanner, "SYMBOL_SCANNER") instead of GetDevices.
I hope this helps someone, it is a truly frustrating issue. If anyone wants a more complete example project feel free to ask.
