Initialization of ComboBox in datagrid, Silverlight 4.0

I have datagrid with list of MyPlayer objects linked to ItemsSource, there are ComboBoxes inside of grid that are linked to a list of inner object, and binding works correctly: when I select one of the item then its value is pushed to data model and appropriately updated in other places, where it is used.

The only problem: initial selections are not displayed in my ComboBoxes. I don't know why..?

Instance of the ViewModel is assigned to view DataContext. Here is grid with ComboBoxes (grid is binded to the SquadPlayers property of ViewModel):

    <data:DataGrid ="True" AutoGenerateColumns="False" ItemsSource="{Binding SquadPlayers}">
        <data:DataGrid.Columns>
            <data:DataGridTemplateColumn Header="Rig." Width="50">
                <data:DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <ComboBox SelectedItem="{Binding Rigid, Mode=TwoWay}"
                                  ItemsSource="{Binding IntLevels, Mode=TwoWay}"/>
                    </DataTemplate>
                </data:DataGridTemplateColumn.CellTemplate>
            </data:DataGridTemplateColumn>
        </data:DataGrid.Columns>
    </data:DataGrid>

Here is ViewModel class ('_model_DataReceivedEvent' method is called asynchronously, when data are received from server):

public class SquadViewModel : ViewModelBase<SquadModel>
{
    public SquadViewModel()
    {
        SquadPlayers = new ObservableCollection<SquadPlayer>();
    }

    private void _model_DataReceivedEvent(开发者_如何学GoList<SostavPlayerData> allReadyPlayers)
    {
        TeamTask task = new TeamTask { Rigid = 1 };
        foreach (SostavPlayerData spd in allReadyPlayers)
        {
            SquadPlayer sp = new SquadPlayer(spd, task);
            SquadPlayers.Add(sp);
        }
        RaisePropertyChanged("SquadPlayers");
    }

And here is SquadPlayer class (it's objects are binded to the grid rows):

public class SquadPlayer : INotifyPropertyChanged
{
    public SquadPlayer(SostavPlayerData spd)
    {
        _spd = spd;

        Rigid = 2;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private int _rigid;
    public int Rigid
    {
        get { return _rigid; }
        set
        {
            _rigid = value;
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs("Rigid"));
            }
        }
    }

    private readonly ObservableCollection<int> _statIntLevels = new ObservableCollection<int> { 1, 2, 3, 4, 5 };
    public ObservableCollection<int> IntLevels { get { return _statIntLevels; } }

It is expected to have all "Rigid" comboboxes set to "2" value, but they are not selected (items are in the drop-down list, and if any value is selected it is going to ViewModel).

What is wrong with this example? Any help will be welcome.

Thanks.

Change the order of your XAML to

ItemsSource="{Binding IntLevels, Mode=TwoWay}" 
SelectedItem="{Binding Rigid, Mode=TwoWay}"

I know it seems funny but I have had this problem before. It is attempting to bind the SelectedValue before the ItemSource exists, which is why after the initialization everything works.