/// <summary>
/// Completes the task gracefully when canceled.
/// </summary>
/// <param name="sender">Background task instance.</param>
/// <param name="reason">Cancellation reason.</param>
private void OnTaskCancelled(IBackgroundTaskInstance sender, BackgroundTaskCancellationReason reason)
{
// Release hardware resources
Debug.WriteLine("Disconnecting from Navio board.");
_board?.Dispose();
// End execution
Debug.WriteLine("Application finished.");
_taskDeferral.Complete();
}
/// <summary>
/// Returns the current <see cref="INavioBoard"/> or creates it the first time.
/// </summary>
/// <param name="model">Hardware model.</param>
/// <returns>Hardware interface for the requested model when successful.</returns>
/// <remarks>
/// The requested hardware model must be the same, otherwise any existing board
/// is disposed and an attempt made to create a board of the new model.
/// </remarks>
public static INavioBoard Connect(NavioHardwareModel model)
{
// Thread-safe lock
lock (_lock)
{
// Check existing board when present
if (_board != null)
{
// Return existing board when present
if (_board.Model == model)
{
return(_board);
}
// Dispose existing board when not null and different model (just in case)
_board.Dispose();
_board = null;
}
// Create new board
switch (model)
{
case NavioHardwareModel.Navio1:
return(_board = new Navio1Board());
case NavioHardwareModel.Navio1Plus:
return(_board = new Navio1PlusBoard());
case NavioHardwareModel.Navio2:
return(_board = new Navio2Board());
default:
// Invalid value or unsupported
throw new ArgumentOutOfRangeException(nameof(model));
}
}
}