Question

This question looks like this one :
Programmatically binding List to ListBox
but as far as my example is concerned, the answers given in this post doesn’t work for me !
Anyway, I looked at about 10/15 similar posts but none worked

Here is my xaml code :

<Grid>
    <ListBox Name="ListBoxx"/>
</Grid>

And here is the code behind :

namespace WpfApplication1
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            ObservableCollection<string> MyCollection = new ObservableCollection<string>();

            Random random = new Random();
            System.Timers.Timer aTimer = new System.Timers.Timer();
            aTimer.Elapsed += (sender, e) =>
            {
                MyCollection.Add(random.Next(0, 100).ToString());
            };
            aTimer.Interval = 500;
            aTimer.Enabled = true;

            Binding myBinding2 = new Binding();
            myBinding2.Source = this;
            myBinding2.Path = new PropertyPath("MyCollection");
            ListBoxx.SetBinding(ListBox.ItemsSourceProperty, myBinding);
        }
    }
}

As far as I know, my class doesn’t have to inherit from INotifyPropertyChanged cause I use an ObservableCollection.

I don’t wanna use a {Binding} in xaml code.

I tried this code :

ListBoxx.ItemsSource = MyCollection;

this “works” but I got a thread crash. I know I can use Dispatcher to fix it but it doesn’t fix with my code. I wanna use a “real” binding (configurable) like in my code snippet.

The result is that I got no error but the ListBox just doesn’t update :/

I tried to add the lines :

MyCollection.Add("aaa");
MyCollection.Add("bbb");
MyCollection.Add("ccc");
MyCollection.Add("ddd");

but I don’t get anything in my application so I really think this is a binding problem. Anyway, I’m SURE that my Timer is OK, The problem’s not here.

I tried too to get MyCollection as Property like this :

private ObservableCollection<string> _MyCollection = new ObservableCollection<string>();
public ObservableCollection<string> MyCollection { get { return _MyCollection; } }

but it doesn’t work too :/ (no error but no update)

Answer 1

The code you posted is going to fail because “MyCollection” isn’t a property in MainWindow. Your Visual Studio output window is probably showing binding errors.

Additionally you indeed need to dispatch the changes you make to the collection, you can use a DispatcherTimer to do this. There should be errors in the output window about that too.

The code below works:

public partial class MainWindow : Window
{
    public ObservableCollection<string> MyCollection { get; set; }

    public MainWindow()
    {
        InitializeComponent();
        MyCollection = new ObservableCollection<string>();

        Random random = new Random();
        DispatcherTimer aTimer = new DispatcherTimer();
        aTimer.Tick += (sender, e) =>
        {
            MyCollection.Add(random.Next(0, 100).ToString());
        };
        aTimer.Interval = new TimeSpan(0,0,0,0,500);
        aTimer.Start();

        Binding myBinding2 = new Binding();
        myBinding2.Source = this;
        myBinding2.Path = new PropertyPath("MyCollection");
        ListBoxx.SetBinding(ListBox.ItemsSourceProperty, myBinding2);
    }
}