Help with WIA programming

Help with WIA programming

Post by axis » Sat, 28 Jun 2003 23:36:42



This is in XP/ME. I'm registering my program so that it appears in Control
Panel > Scanners and Cameras , for the Device Online event. I execute:

pWiaDevMgr->RegisterEventCallbackProgram(WIA_REGISTER_EVENT_CALLBACK,
             NULL,
             &WIA_EVENT_DEVICE_CONNECTED,
            app_bstr,
            app_name_bstr,
            app_desc_bstr,
            icon_bstr);

and it works great. Now, later on I want to be able to un-register it, I
execute:

 hr =
pWiaDevMgr->RegisterEventCallbackProgram(WIA_UNREGISTER_EVENT_CALLBACK,
             NULL,
             &WIA_EVENT_DEVICE_CONNECTED,
            app_bstr,
            app_name_bstr,
            app_desc_bstr,
            icon_bstr);

with the exact same values for app/app_name/app_desc/icon, and it gives me
the error : "parameter incorrect".

Not very descriptive. All the parameters are allocated and hold the values I
expect them to...

Any ideas? I know I can use other RegisterEventCallback functions to recieve
messages directly in my app, but I need to register the application this
way.

Thanks in advance.

 
 
 

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