How to detect if the surface keyboard is attached?

Question

I need to implement certain functions only when the keyboard is attached to the surface. Is there a way I can detect when the surface keyboard is attached or removed ?

I tried this code on Surface:

function getKeyboardCapabilities()
{   
   var keyboardCapabilities = new Windows.Devices.Input.KeyboardCapabilities();
   console.log(keyboardCapabilities.keyboardPresent);

}

The result was always '1' even when the keyboard was not connected.

Answer 1

I used this code to identify when a keyboard is connected to a Surface:

var keyboardWatcher = (function () {
    // private
    var keyboardState = false;

    var watcher = Windows.Devices.Enumeration.DeviceInformation.createWatcher();
    watcher.addEventListener("added", function (devUpdate) {
    // GUID_DEVINTERFACE_KEYBOARD
        if ((devUpdate.id.indexOf('{884b96c3-56ef-11d1-bc8c-00a0c91405dd}') != -1) && (devUpdate.id.indexOf('MSHW0007') == -1)    ) {
            if (devUpdate.properties['System.Devices.InterfaceEnabled'] == true) {
                // keyboard is connected 
                keyboardState = true;
            }
        }
    });
    watcher.addEventListener("updated", function (devUpdate) {

        if (devUpdate.id.indexOf('{884b96c3-56ef-11d1-bc8c-00a0c91405dd}') != -1) {
            if (devUpdate.properties['System.Devices.InterfaceEnabled']) {
                // keyboard is connected 
                keyboardState = true;
            }
            else {
                // keyboard disconnected
                keyboardState = false;
            }
        }
    });

    watcher.start();

    // public
    return {
        isAttached: function () {
            return keyboardState;
        }
    }

})(); 

Then call KeyboardWatcher.isAttached() whenever you need to check the status of the keyboard.