MVVM Light is a great cross-platform MVVM Framework, and was chosen to be used in this example. However, it isn’t required to get the same results.
FlipViews were a great addition to the WIndows Control family for Windows Phone and Windows Store applications. It’s easily customized, simple to use, and can give your app a user friendly experience for anything from an image gallery, to a news reader. So let’s get to the code.
Let’s first build the model we are going to use for each of our views in our FlipView. I’m using a PCL for my Models and ViewModels and a Windows Phone 8.1 project for the xaml, but it works in the same fashion for Windows Store.
Here is our model:
public class RotatorItem
{
public string Title { get; set; }
public string ImageUri { get; set; }
public string Subtitle { get; set; }
}
Now let’s look at a simple ViewModel with MVVM Light to hold our collection of SimpleRotatorItems.
public class LandingRotatorPageViewModel : ViewModelBase
{
#region Private Properties
private ObservableCollection<RotatorItem> _rotatorItems;
private RotatorItem _activeItem;
#endregion
#region Public Properties
public ObservableCollection<RotatorItem> RotatorItems
{
get
{
return _rotatorItems;
}
set
{
Set(() => RotatorItems, ref _rotatorItems, value);
}
}
public RotatorItem ActiveItem
{
get
{
return _activeItem;
}
set
{
Set(() => ActiveItem, ref _activeItem, value);
}
}
#endregion
public LandingRotatorPageViewModel()
{
var rotatorItems = new ObservableCollection<RotatorItem>();
rotatorItems.Add(new RotatorItem { ImageUri = "/Assets/Logo.scale-240.png", Title = "Title 1", Subtitle = "Subtitle 1"});
rotatorItems.Add(new RotatorItem { ImageUri = "/Assets/Logo.scale-240.png", Title = "Title 2", Subtitle = "Subtitle 2" });
rotatorItems.Add(new RotatorItem { ImageUri = "/Assets/Logo.scale-240.png", Title = "Title 3", Subtitle = "Subtitle 3" });
rotatorItems.Add(new RotatorItem { ImageUri = "/Assets/Logo.scale-240.png", Title = "Title 4", Subtitle = "Subtitle 4" });
RotatorItems = rotatorItems;
ActiveItem = rotatorItems.First();
}
}
Let’s go ahead now and get our markup done for our page with the FlipView:
<FlipView x:Name="SimpleFlipView" ItemsSource="{Binding RotatorItems}" Grid.Row="1" SelectionChanged="FlipView_SelectionChanged">
<FlipView.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="200" />
<RowDefinition Height="120" />
<RowDefinition Height="80" />
</Grid.RowDefinitions>
<Image Source="{Binding ImageUri}" Height="150" Grid.Row="0" VerticalAlignment="Top" Margin="0,50,0,0"/>
<TextBlock TextWrapping="Wrap" TextAlignment="Center" Grid.Row="1" Text="{Binding Title}" FontSize="30" HorizontalAlignment="Center" Margin="20"></TextBlock>
<TextBlock TextWrapping="Wrap" TextAlignment="Center" Grid.Row="2" FontSize="20" HorizontalAlignment="Center" Margin="20">
<Run Text="{Binding Subtitle}"></Run>
</TextBlock>
</Grid>
</DataTemplate>
</FlipView.ItemTemplate>
</FlipView>
Last but not least, let’s make sure our ViewModel is bound to our Page in our page Class:
public sealed partial class MainPage : Page
{
private LandingRotatorPageViewModel _vm;
public MainPage()
{
this.InitializeComponent();
_vm = new LandingRotatorPageViewModel();
this.DataContext = _vm;
}
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached.
/// This parameter is typically used to configure the page.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
}
}
Now that the Page’s DataContext is set to our ViewModel, the binding we placed on the FlipView element ‘ItemSource=”{Binding RotatorItems}”‘ will bind our FlipView’s Items to the items we created in the constructor for our ViewModel, and will use our ItemTemplate to create our items from the fields on the RotatorItems.
Now let’s take a look at our final result:
So there you have it. An easy solution to using the Windows FlipView Control to display content that is bound to a ViewModel.
Alex Dunn 