user interface - WPF and cross thread operations

Question

I have a small WPF application where I'm simulating movement which is detected by a sensor. I fake that movement occurs after 1 minute and it stops after 2 minutes. Below is my code:

 public event Action OnMotionDetected;
        public event Action OnMotionReset;
        private DateTime startTime = DateTime.Now;

        public MotionDetectionService()
        {
            startTime = DateTime.Now;
            System.Threading.Thread mockThread = new System.Threading.Thread(new System.Threading.ThreadStart(StartMock));
            mockThread.Start();
        }

     private void StartMock()
            {
                while (DateTime.Now < startTime.AddMinutes(1))
                {
                    System.Threading.Thread.Sleep(1000);
                    Console.WriteLine("Remaining: " + (startTime.AddMinutes(1) - DateTime.Now).ToString());
                }
                FireMoveEvent();
                while (DateTime.Now < startTime.AddMinutes(2))
                {
                    System.Threading.Thread.Sleep(1000);
                    Console.WriteLine("Remaining: " + (startTime.AddMinutes(2) - DateTime.Now).ToString());
                }
                FireMoveEvent();
            }

            private void FireMoveEvent()
            {
                if(OnMotionDetected != null)
                {
                    OnMotionDetected();
                }
            }

            private void FireResetEvent()
            {
                if (OnMotionReset != null)
                {
                    OnMotionReset();
                }
            }

When the thread fires the event my UI updates, but it says that it cannot update because the UI elements was generated on another thread.

Any ideas on how to solve?

Answer 1

You can use Dispatcher.Invoke() to marshall onto the UI thread.

Please see: Making sure OnPropertyChanged() is called on UI thread in MVVM WPF app