Question

I’m got a collection of object and inside the object there are going to be some properties and a dynamic list of objects. I’m my example this is illustrated with the Name and Numbers properties.

Now I got it to look right, but I’m having problems changing the data from code behind.
If I change something in the mList inside the MainWindow() it’s correctly beeing displayed on my DataGrid, but If I do the same inside a Click even’t nothing happens.

I have looked at INotifyPropertyChanged, but that did’nt changed nothing.

Please not that this is a sample project I created for this question

MyList.cs

public class MyObject : IEnumerable<object[]>
{
    public string Name { get; set; }
    public int[] Numbers { get; set; }

    public IEnumerator<object[]> GetEnumerator()
    {
        var obj = new object[Numbers.Length + 1];
        obj[0] = Name;
        for (var i = 0; i < Numbers.Length; i++)
            obj[i + 1] = Numbers[i];

        yield return obj;
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

MainWindow.xaml.cs

private List<MyObject> mList;
    public MainWindow()
    {
        InitializeComponent();

        mList = new List<MyObject>
                    {
                        new MyObject {Name = "List 1", Numbers = new[] {1, 2, 3, 4}},
                        new MyObject {Name = "List 2", Numbers = new[] {1, 2, 3, 4}},
                        new MyObject {Name = "List 3", Numbers = new[] {1, 2, 3, 4}}
                    };

        dataGrid.ItemsSource = mList;
        var columnNames = new[] {"List", "Number 1", "Number 2", "Number 3", "Number 4"};
        AddColumns(dataGrid, columnNames);

        mList[0].Name = "Test";   //Works
        mList[0].Numbers[0] = 123;  //Works

    }
    private void AddColumns(DataGrid gv, string[] columnNames)
    {
        for (int i = 0; i < columnNames.Length; i++)
            gv.Columns.Add(new DataGridTextColumn()
                               {
                                   Header = columnNames[i],
                                   Binding = new Binding(String.Format("[{0}]", i))
                               });

    }

    private void ButtonClick(object sender, RoutedEventArgs e)
    {
        mList[0].Name = "Test test";   //Don't work
        mList[0].Numbers[0] = 234;  //Don't work
    }
}

MainWindow.xaml

<StackPanel>
    <Button Click="ButtonClick">Test</Button>
    <DataGrid Height="Auto" Name="dataGrid" AutoGenerateColumns="False"/>
</StackPanel>

EDIT
This is a mofidifed MyObject, I’m still not able to change the Name from code

 public class MyObject : IEnumerable<object[]>, INotifyPropertyChanged
{
    private string _name;
    public string Name
    {
        get { return _name; }
        set { _name = value;
            OnPropertyChanged("Name");
        }
    }

    public int[] Numbers { get; set; }

    public IEnumerator<object[]> GetEnumerator()
    {
        var obj = new object[Numbers.Length + 1];
        obj[0] = Name;
        for (var i = 0; i < Numbers.Length; i++)
            obj[i + 1] = Numbers[i];

        yield return obj;
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }
}

Answer 1

The problem is that with the following code

Binding = new Binding(String.Format("[{0}]", i))

you bind each column to a Path like [i].

For example in the case of column 0 (binding to property Name) you need

new Binding("Name")

With this code you should see your datagrid update after executing

mList[0].Name = "Test test";  

The same concept is valid for the other columns