Problem:

I'm looking to create a DataGrid that updates automatically as new objects gets added into an ObservableCollection. As a prototype, I've made a Timer that adds new, unique objects into the ObservableCollection. The class in question inherits from a custom ObservableObject class that inherits from the INotifyPropertyChanged interface. Using breakpoints, I can see that the ObservableCollection updates, the ObservableObject class gets called and sets the right values, but the DataGrid never displays anything.

MainWindow.xaml:

<DataGrid Name="dg" ItemsSource="{Binding Path=DataColl, Mode=TwoWay}" >

</DataGrid>

MainWindow.xaml.cs:

public partial class MainWindow : Window
{

    public ObservableCollection<DataClass> DataColl = new ObservableCollection<DataClass>();
    public MainWindow()
    {
        InitializeComponent();

        this.DataContext = this;

        Timer aTimer;
        aTimer = new Timer();
        aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
        aTimer.Interval = 5000;
        aTimer.Enabled = true;

    }
    int index = 0;
            private void OnTimedEvent(object sender, ElapsedEventArgs e)
    {
        DataColl.Add(new DataClass() { ID = index, time = string.Format("{0:HH:mm:ss tt}", DateTime.Now),source="AIS"});
        index++;

    }

}

DataClass.cs

public class DataClass : ObservableObject
{
    private int _id;

    public int ID
    {
        get
        {
            return _id;
        }
        set
        {
            SetProperty(ref _id, value);
        }
    }
    public string time { get; set; }
    public string source { get; set;}
}

ObservableObject.cs

public class ObservableObject : INotifyPropertyChanged
{
        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged([CallerMemberName] string propName = null)
        {
            var handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(propName));
            }
        }

        protected bool SetProperty<T>(ref T storage, T value,
            [CallerMemberName] String propertyName = null)
        {
            if (Equals(storage, value)) return false;
            storage = value;
            OnPropertyChanged(propertyName);

            return true;
        }
}

Any help is appreciated!

Change your observable collection declaration as

private ObservableCollection<DataClass> dataColl;
        public ObservableCollection<DataClass> DataColl
        {
            get { return dataColl; }
            set { dataColl = value; }
        }

initialize the collection inside the constructor and change your timer event as

     private void OnTimedEvent(object sender, ElapsedEventArgs e)
            {
                Dispatcher.Invoke(() =>
                {
                    DataColl.Add(new DataClass() { ID = index, time = string.Format("{0:HH:mm:ss tt}", DateTime.Now), source = "AIS" });
                    index++;
                });
           }

more