Symbol scanner stops scanning

[John Smith]

Hi,

Are there any known problems with the Symbol API scanner functions? I have a
VB.Net Windows CE scanner application which uses the Symbol.barcode.reader
class that just stops scanning after a while. No scanner beam. No scanner
light on the device. The worst thing is that the problem is frustratingly
intermittent, which suggests that there is more to it than a possible
application error. All objects are being carefully disposed of once they are
no longer required. The only solution is to stop and re-start the
application, which we cannot afford. Earlier threads such as the one titled
"Scanner Uses Memory" indicate that I'm not the only one experiencing
problems of this nature. It appears that the problem has a slight
relationship with the opening and closing of forms, but once again, this
relationship is intermittent at best. This problem is costing our
organization a lot of time and money and the support provided by Symbol has
been non-existent.

Many thanks,

John

 

[Paul G. Tobey [eMVP]]

If exiting just your application fixes the problem, that suggests that your
code is sometimes putting the scanner into a state where it doesn't work
(and the initialization that you do the next time the program runs is fixing
it). Are you using threading in your application? Perhaps there's a race
condition and, depending on who wins, the scanner might stop working...

Paul T.

 

[Lars Black]

application error. All objects are being carefully disposed of once they

are
no longer required. The only solution is to stop and re-start the
application, which we cannot afford. Earlier threads such as the one
titled

We have a number of application running on PPT88xx and PDT80xx series and we
have no problems (more). One of the applications is used for Warehouse
Management and often reaches 1000 scans a day.
We had a few problems back when the application was new, but carefully
disposing objects and enabling / disabling the scanner appropriate fixed the
problems. Also, be sure to use version 1.01 (or newer if that exists) of the
Symbol SDK.

We have a global instance of the scanner object and the forms that needs to
receive input from the scanner, attaches the readerNotify event in their
OnActivated method and releases it again in OnDeactivated. Two forms trying
to get notifications at the same time will make a scenario like your are
describing.

HTH

Cheers,
Lars