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POWP7 - Unable to databind to the same object from two pages
 

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  1. POWP7 - Unable to databind to the same object from two pages
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    <ol> <li>Page1 creates and databinds to a new instance of Foo (call it theFoo)</li> <li>theFoo.Name is set via textbox from Page1</li> <li>theFoo is saved to a globally accessible data structure (list of Foos, whatever)</li> <li>navigate from Page1 to Page2</li> <li>Page2 databinds to the global list of Foos, to display all Foo instances</li> </ol> <p>When I do this, I can verify that the Foo instance is added to the global list. But Page2 never shows any Foos.</p> <p>If I manually add Foos to the global list (in code instead of from Page1), then navigate to Page2 without ever navigating to Page1 at all, I see Foos displayed in Page2.</p> <p>What's the issue here?</p> <p>Update:</p> <p>Here's some relevant code...</p> <p><b>Item.cs (Data and global storage structure)</b></p> <pre><code>public class Item { public string Name { get; set; } } internal static class ItemRepos { private static List&lt;Item&gt; _items = new List&lt;Item&gt;(); public static Item New() { return new Item(); } public static int Count { get { return _items.Count; } } public static IEnumerable&lt;Item&gt; GetAll() { return _items; } public static Item Get( string name ) { return _items.SingleOrDefault( item =&gt; item.Name == name ); } public static void Save( Item item ) { if ( _items.Contains( item ) == false ) { _items.Add( item ); } } public static void Remove( Item item ) { _items.Remove( item ); } } </code></pre> <p><b>Relevant Page1.xaml fragment</b></p> <pre><code>&lt;TextBlock Text="Name:" Grid.Row="0" Grid.Column="0" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="5" /&gt; &lt;TextBox x:Name="txtName" Grid.Row="0" Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Center" Text="{Binding Name}" /&gt; </code></pre> <p><b>Page1.xaml.cs</b></p> <pre><code>public partial class ItemDetail : PhoneApplicationPage { public ItemDetail() { InitializeComponent(); } protected override void OnNavigatedTo( NavigationEventArgs e ) { base.OnNavigatedTo( e ); this.DataContext = ItemRepos.New(); } private void Nav( object sender, EventArgs e ) { NavigationService.Navigate( new Uri( "/Page2.xaml", UriKind.RelativeOrAbsolute ) ); } private void Save( object sender, EventArgs e ) { ItemRepos.Save( (Item) this.DataContext ); } } </code></pre> <p><b>Relevant Page2.xaml fragment</b></p> <pre><code>&lt;controls:PivotItem Header="A-Z"&gt; &lt;ListBox x:Name="listAZ" ItemsSource="{Binding}"&gt; &lt;ListBox.ItemTemplate&gt; &lt;DataTemplate&gt; &lt;TextBlock Text="{Binding Name}" /&gt; &lt;/DataTemplate&gt; &lt;/ListBox.ItemTemplate&gt; &lt;/ListBox&gt; &lt;/controls:PivotItem&gt; </code></pre> <p><b>Page2.xaml.cs</b></p> <pre><code>public partial class ViewItems : PhoneApplicationPage { public ViewItems() { InitializeComponent(); } protected override void OnNavigatedTo( NavigationEventArgs e ) { base.OnNavigatedTo( e ); this.DataContext = ItemRepos.GetAll(); } } </code></pre>
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    1. USJoshL
    1. USJoshL
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    1. COWhat is the type of your global data structure? And exactly how do you add theFoo inside?
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      1. POWP7 - Unable to databind to the same object from two pages
      1. USKevin Gosse
 

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