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POBinding from View-Model to View-Model of a child User Control in Silverlight? 2 sources - 1 target
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  1. POBinding from View-Model to View-Model of a child User Control in Silverlight? 2 sources - 1 target
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    copied!<p>So i have a UserControl for one of my Views and have another 'child' UserControl inside that. </p> <p>The outer 'parent' UserControl has a Collection on its View-Model and a Grid control on it to display a list of <code>Items</code>. </p> <p>I want to place another UserControl inside this UserControl to display a form representing the details of one <code>Item</code>. </p> <p>The parent UserControl's View-Model already has a property on it to hold the currently selected <code>Item</code> and i would like to bind this to a DependancyProperty on the child UserControl. I would then like to bind that DependancyProperty to a property on the child UserControl's View-Model. </p> <p>I can then set the DependancyProperty once in XAML with a binding expression and have the child UserControl do all its work in its View-Model like it should.</p> <p>The code i have looks like this..</p> <p>Parent UserControl:</p> <pre><code>&lt;UserControl x:Class="ItemsListView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" DataContext="{Binding Source={StaticResource ServiceLocator}, Path=ItemsListViewModel}"&gt; &lt;!-- Grid Control here... --&gt; &lt;ItemDetailsView Item="{Binding Source={StaticResource ServiceLocator}, Path=ItemsListViewModel.SelectedItem}" /&gt; &lt;/UserControl&gt; </code></pre> <p>Child UserControl:</p> <pre><code>&lt;UserControl x:Class="ItemDetailsView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" DataContext="{Binding Source={StaticResource ServiceLocator}, Path=ItemDetailsViewModel}" ItemDetailsView.Item="{Binding Source={StaticResource ServiceLocator}, Path=ItemDetailsViewModel.Item, Mode=TwoWay}"&gt; &lt;!-- Form controls here... --&gt; &lt;/UserControl&gt; </code></pre> <p><strong>EDIT:</strong> Heres how i created the Dependancy Proeprty on the child UC:</p> <pre><code>public partial class ItemDetailsView : UserControl { private static readonly DependencyProperty itemProperty; static ItemDetailsView() { ItemDetailsView.itemProperty = DependencyProperty .Register("Item", typeof(Item), typeof(ItemDetailsView), null); } public Item Item { get { return (Item)GetValue(ItemDetailsView.itemProperty); } set { SetValue(ItemDetailsView.itemProperty, value); } } public static Item GetItem(DependencyObject target) { return (Item)target.GetValue(itemProperty); } public static void SetItem(DependencyObject target, Item value) { target.SetValue(itemProperty, value); } } </code></pre> <p>The selected <code>Item</code> is bound to the DependancyProperty fine. However from the DependancyProperty to the child View-Model does not. </p> <p>It appears to be a situation where there are two concurrent bindings which need to work but with the same target for two sources.</p> <p>Why won't the second (in the child UserControl) binding work?? Is there a way to acheive the behaviour I'm after??</p> <p>Cheers.</p>
 

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