同一页面上的两个集合

Question

I have a page that already has a DataContext.

When i change the pivot item, I need to bind another list to another collection.

How to achieve this?

Here is the first DataContext that shows first pivotitem info.

protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        base.OnNavigatedTo(e);

        if (NavigationContext.QueryString.TryGetValue("id", out _embarqueId))
        {
            String json = JsonConvert.SerializeObject(_embarqueId);

            using (IntrepService service = new IntrepService())
            {
                String retornojson = service.ObterDetalhesEmbarque(json);

                EmbarqueAtual = JsonConvert.DeserializeObject<EmbarqueViewModel>(retornojson);

                DataContext = EmbarqueAtual;
            }

            VerificaConclusao();
        }
    }

Then I try to load the second collection to the listbox, but doesn't work:

private void Pivot_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (!_itemsareloaded && ((PivotItem)pivot.SelectedItem).Header.Equals("itens"))
        {
            using (IntrepService service = new IntrepService())
            {
                String json = JsonConvert.SerializeObject(_embarqueId);

                var retorno = service.ObterItensEmbarque(json);

                ItensDoEmbarque = JsonConvert.DeserializeObject<ObservableCollection<ItemDeEmbarqueViewModel>>(retorno);
                lstItens.DataContext = ItensDoEmbarque;
            }

        }
    }

Answer 1

You should have one ViewModel to hold all of your data that you want to bind to. Set this ViewModel as your datacontext.

public class ViewModel : INotifyPropertyChanged
{
    private ObservableCollection<ItemDeEmbarqueViewModel> _itensDoEmbarque;
    private EmbarqueViewModel _embarqueAtual;

    public ViewModel()
    {
        ItensDoEmbarque = new ObservableCollection<ItemDeEmbarqueViewModel>();
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public ObservableCollection<ItemDeEmbarqueViewModel> ItensDoEmbarque
    {
        get { return _itensDoEmbarque; }
        set
        {
            _itensDoEmbarque= value;
            OnPropertyChanged("ItensDoEmbarque");
        }
    }

    public EmbarqueViewModel EmbarqueAtual
    {
        get { return _embarqueAtual; }
        set
        {
            _embarqueAtual = value;
            OnPropertyChanged("EmbarqueAtual");
        }
    }

    protected virtual void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Within your OnNavigatedTo method set both of the properties and set the DataContext to be this object. You xaml would need to change to bind to the properties of these items instead of {Binding}

You can set the collections that the PivotItem will be bound to ahead of time without worry of rendering delay. PivotItems delay rendering until they are shown.