Datagrid not refreshed when bound datatable is modified using another thread

Question

Scenario: There is a datagrid bound to datatable in View Model. This datatable reference is injected to Model and it is updated using a background thread.

Result: Datagrid is not immediately refreshed as soon as underlying datatable is updated but if I switch between different tabs then datagrid is showing latest values present in datatable.

Answer 1

A common approach would be to start a background task for updating the datatable async and hook up on finishing this operation with .ContinueWith to update the UI.

Task.Factory.StartNew(() => { ..Do the background DataTable update.. })
            .ContinueWith(task => {.. Update the UI.. });

But you have to dispatch the .ContinueWith action into the Main Thread, due to the STA restriction.

Task.Factory.StartNew(() => { ..Do the background DataTable update.. })
                .ContinueWith(task => 
                             {
                                var dispatcher = Application.Current == null
                                     ? Dispatcher.CurrentDispatcher
                                     : Application.Current.Dispatcher;

                                Action action = delegate()
                                                {
                                                    //Update UI (e.g. Raise NotifyPropertyChanged on bound DataTable Property)
                                                 };

                               dispatcher.Invoke(DispatcherPriority.Normal, action);
});

Since the Dispatching operation is a repeating operation I would suggest to put the logic into a ViewModelBase Class to reduce the code like this:

Task.Factory.StartNew(() => ..Do the background DataTable update..)
            .ContinueWith(task => Dispatch(() =>
                {
                    //Update UI
                }));

To Update the UI you can use the common notify of INotifyPropertyChanged to raise the property changed event on the bound datatable.