Windows Mobile 5.0 State and Notifications Broker - More resources

Rupesh;

The exact way you do it depends on whether you’re using managed or native code.

In managed code you check to see if a phone call is active by checking the value of SystemState.PhoneCallTalking. To be notified that a call is entering or leaving the active talking state do the following:

SystemState _phoneCallTalking; // should be class-level not local to a function
_phoneCallTalking = new SystemState(SystemProperty.PhoneCallTalking);
_phoneCallTalking.Changed += new ChangedEventHandler(MyPhoneCallTalkingHandler);

For native code you use the following 4 constants from snaphi.h
SN_PHONECALLTALKING_ROOT
SN_PHONECALLTALKING_PATH
SN_PHONECALLTALKING_VALUE
SN_PHONECALLTALKING_BITMASK

Use the RegistryGetDWORD function to retrieve the value and the RegistryNotifyWindow function to be notified of a change in state.

You can find a detailed description of working with both the managed and native APIs at http://msdn2.microsoft.com/en-us/library/aa456240.aspx.

That should do it :-)

- Jim

Oh, I forgot to include this...

You can find the complete list of Windows Mobile 5.0 state values at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/mobilesdk5/html/wce50constatstorbaseproperties.asp

-Jim

I really would like to use managed code to receive notifications of changes to
[HKEY_LOCAL_MACHINE\System\State\Hardware]
"Bluetooth"=dword:00000001.

But it looks like I can only do that in native code.

Is that true?

David

David;

You can receive notifications in managed code to any State & Notifications value. The SystemState class and SystemProperty enum that we most frequently use provides simplified handling for the common pre-defined state values but it's not the only way to receive notifications.

For values that are not covered by SystemState/SystemProperty, you can use the RegistryState class which allows you to explicitly specify the registry key and value that you'd like to monitor. For the case you've mentioned you'd do the following.

RegistryState _hardwareBluetooth;
void Form1_Load( ..., ...)
{
_hardwareBluetooth = new RegistryState(registryKey, registryValueName);
_hardwareBluetooth.Changed += new ChangeEventHandler(HardwareBluetoothChanged);

int theValue = (int)_hardwareBluetooth.CurrentValue;
// ....
}

Other then the constructor, using the RegistyState class is just like using the SystemState class. In fact, the SystemState class actually contains a private instance of the RegistryState class that does all of the work. The SystemState class is just a slightly more friendly wrapper

Hope this helps.

-Jim

Ooops...

I forgot to include the two constant definitions that the RegistryState constructor uses in the above sample code.

const string registryKey = @"HKEY_LOCAL_MACHINE\System\State\Hardware";
const string registryValueName = @"Bluetooth";

There... that should do the trick. :-)

-Jim

That worked.

For completeness, one also needs
public void HardwareBluetoothChanged(object sender, ChangeEventArgs args)
{
// registry changed
// RegistryState state = (RegistryState)sender;
}

Thanks,
David

David;

Agreed - I was focusing on the RegistryState class usage itself but the Changed Event handler method does complete the story. :-)

Thanks,
Jim