How to add WPF UIElement created in another thread to a Grid created in main thread?

Question

I have a WPF project, I need to send my heavy process to another thread and then get the result and send it to main thread. The expensive operation is to retrieve data from the database and populate a datagrid with data and then send it to main thread to be added to a grid. I created a thread, instantiate and run it:

Thread thread = new Thread(new ThreadStart(myHeavyProcess));
thread.SetApartmentState(ApartmentState.STA);
thread.Start();

Here is my method:

private void myHeavyProcess()
    {
        DataGrid datagrd = new DataGrid();
        //....
        //populate the datagrid with data 
        //...

        grdCharts.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, (Action)(() => grdCharts.Children.Add(datagrd )));
    }

grdCharts is created in main thread and datagrd is created in the new thread, int the last line I tried to add the datagrd to grdcharts using Dispatcher as it is from a different thread.

The question is that since grdCharts is in the main thread and datagrd in the new thread how can I add datagrd to grdCharts ? or in general how can we copy one UIElement from a thread to another?

Note: I need to populate datagrid in another thread since it is the expensive process I was talking about.

Closed. See my answer in the Duplicate question to understand how to properly use WPF UI features in a multi-threaded scenario. — Federico Berasategui, Jul 12 '14 at 04:30

score 2 · Answer 1 · answered Jul 12 '14 at 03:53

Ideally UI elements are not supposed to be created in background threads

To overcome this issue you may perhaps prepare data in background thread and then create datagrid in UI thread and assign the prepared data.

example

    private void myHeavyProcess()
    {
        ObservableCollection<object> data = new ObservableCollection<object>();
        //....
        //prepare data 
        //...

        grdCharts.Dispatcher.BeginInvoke(
            (Action<IEnumerable>)(d => grdCharts.Children.Add(new DataGrid() { ItemsSource = d })), 
            DispatcherPriority.Background, 
            new object[] { data });
    }

How to add WPF UIElement created in another thread to a Grid created in main thread?

1 Answers1