damirarh

public class IncrementalLoadingBehavior : Behavior<LongListSelector>
{
    public ICommand LoadCommand { get; set; }

    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.ItemRealized += OnItemRealized;
    }

damirarh

<i:Interaction.Behaviors>
    <b:IncrementalLoadingBehavior LoadCommand="{Binding LoadCommand}" />
</i:Interaction.Behaviors>

damirarh

<phone:LongListSelector cal:Message.Attach="[Event ItemRealized]=[Action LoadMoreItems($eventArgs)]" />

damirarh

public class IncrementalLoadingTrigger : TriggerBase<LongListSelector>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.ItemRealized += OnItemRealized;
    }

    private void OnItemRealized(object sender, ItemRealizationEventArgs e)
    {

damirarh

<i:Interaction.Triggers>
    <t:IncrementalLoadingTrigger>
        <cal:ActionMessage MethodName="LoadMoreItems"/>
    </t:IncrementalLoadingTrigger>
</i:Interaction.Triggers>

damirarh

public ViewModel()
{
    Init();
}

private async void Init()
{
    var file = await Package.Current.InstalledLocation.GetFileAsync(@"Assets\Text.txt");
    Text = await FileIO.ReadTextAsync(file);
}

damirarh

public class BooleanToVisibilityConverter : IValueConverter
{
    public bool Inverted { get; set; }

    public object Convert(object value, Type targetType, object parameter, string language)
    {
        if (!(value is bool))
        {
            return Visibility.Collapsed;
        }

damirarh

<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
    <ProgressBar Value="{Binding Progress}"
                 Minimum="0"
                 Maximum="1"
                 Visibility="{Binding Initialized, Converter={StaticResource InvertedBoolToVisibilityConverter}}"/>
    <TextBlock Text="{Binding Text}" 
               TextWrapping="Wrap"
               Visibility="{Binding Initialized, Converter={StaticResource BoolToVisibilityConverter}}"
               Style="{StaticResource BasicTextStyle}" />
</Grid>

damirarh

private readonly Task _initializingTask;

public ViewModel()
{
    _initializingTask = Init();
}

private async Task Init()
{
    var file = await Package.Current.InstalledLocation.GetFileAsync(@"Assets\Text.txt");

damirarh

var file = await Package.Current.InstalledLocation.GetFileAsync(@"\Assets\Text.txt");
file.CopyAsync(ApplicationData.Current.LocalFolder);