private async void ServiceList_SelectionChanged()
{
var service = (GattDeviceService)((ComboBoxItem)ServiceList.SelectedItem)?.Tag;
CharacteristicList.Items.Clear();
RemoveValueChangedHandler();
IReadOnlyList <GattCharacteristic> characteristics = null;
try
{
// Ensure we have access to the device.
var accessStatus = await service.RequestAccessAsync();
if (accessStatus == DeviceAccessStatus.Allowed)
{
// BT_Code: Get all the child characteristics of a service. Use the cache mode to specify uncached characterstics only
// and the new Async functions to get the characteristics of unpaired devices as well.
var result = await service.GetCharacteristicsAsync(BluetoothCacheMode.Uncached);
if (result.Status == GattCommunicationStatus.Success)
{
characteristics = result.Characteristics;
}
else
{
rootPage.NotifyUser("Error accessing service.", NotifyType.ErrorMessage);
// On error, act as if there are no characteristics.
characteristics = new List <GattCharacteristic>();
}
}
else
{
// Not granted access
rootPage.NotifyUser("Error accessing service.", NotifyType.ErrorMessage);
// On error, act as if there are no characteristics.
characteristics = new List <GattCharacteristic>();
}
}
catch (Exception ex)
{
rootPage.NotifyUser("Restricted service. Can't read characteristics: " + ex.Message,
NotifyType.ErrorMessage);
// On error, act as if there are no characteristics.
characteristics = new List <GattCharacteristic>();
}
foreach (GattCharacteristic c in characteristics)
{
CharacteristicList.Items.Add(new ComboBoxItem {
Content = DisplayHelpers.GetCharacteristicName(c), Tag = c
});
}
CharacteristicList.Visibility = Visibility.Visible;
}
private async void ConnectButton_Click()
{
ConnectButton.IsEnabled = false;
if (!await ClearBluetoothLEDeviceAsync())
{
rootPage.NotifyUser("Error: Unable to reset state, try again.", NotifyType.ErrorMessage);
ConnectButton.IsEnabled = true;
return;
}
try
{
// BT_Code: BluetoothLEDevice.FromIdAsync must be called from a UI thread because it may prompt for consent.
bluetoothLeDevice = await BluetoothLEDevice.FromIdAsync(rootPage.SelectedBleDeviceId);
if (bluetoothLeDevice == null)
{
rootPage.NotifyUser("Failed to connect to device.", NotifyType.ErrorMessage);
}
}
catch (Exception ex) when(ex.HResult == E_DEVICE_NOT_AVAILABLE)
{
rootPage.NotifyUser("Bluetooth radio is not on.", NotifyType.ErrorMessage);
}
if (bluetoothLeDevice != null)
{
// Note: BluetoothLEDevice.GattServices property will return an empty list for unpaired devices. For all uses we recommend using the GetGattServicesAsync method.
// BT_Code: GetGattServicesAsync returns a list of all the supported services of the device (even if it's not paired to the system).
// If the services supported by the device are expected to change during BT usage, subscribe to the GattServicesChanged event.
GattDeviceServicesResult result = await bluetoothLeDevice.GetGattServicesAsync(BluetoothCacheMode.Uncached);
if (result.Status == GattCommunicationStatus.Success)
{
var services = result.Services;
rootPage.NotifyUser(String.Format("Found {0} services", services.Count), NotifyType.StatusMessage);
foreach (var service in services)
{
ServiceList.Items.Add(new ComboBoxItem {
Content = DisplayHelpers.GetServiceName(service), Tag = service
});
}
ConnectButton.Visibility = Visibility.Collapsed;
ServiceList.Visibility = Visibility.Visible;
}
else
{
rootPage.NotifyUser("Device unreachable", NotifyType.ErrorMessage);
}
}
ConnectButton.IsEnabled = true;
}
