Introducing the Model Thread View Thread Pattern

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             x:Class="DanielVaughan.MtvtExample.MainPage"
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                <TextBlock FontSize="20">Example: Model Thread View Thread</TextBlock>
                <TextBlock TextWrapping="Wrap">This example demonstrates how a command can be used to raise CanExecute and Execute handlers in a view model using a dedicated model thread.
                    It also shows how a custom ObserableDictionary can raise collection changed events on the subscriber thread.
                    This means that when the collection changes via the model thread, the collection changed event will be raised on the UI thread, and
                    this prevents cross thread access exceptions. Likewise, property changes, if not subscribed to on the UI thread are raised on the model thread.</TextBlock>
                <StackPanel Orientation="Horizontal">
                    <Button Content="Fire view model command" 
                            cal:Click.Command="{Binding TestCommand}" 
                            Width="169" Height="32"  />
                    <TextBlock Text="{Binding Message}" TextWrapping="Wrap" Margin="5, 0, 0, 0" />
                </StackPanel>
                <StackPanel Orientation="Horizontal">
                    <TextBlock Text="Last string added: "/>
                    <TextBlock Text="{Binding TestString}"/>
                    <TextBlock Text=" | UI Thread ID: "/>
                    <TextBlock x:Name="TextBlock_UIThreadId" />
                    <TextBlock Text=" | View Model Thread ID: "/>
                    <TextBlock Text="{Binding VMThreadId}" />
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                <ListBox ItemsSource="{Binding ExampleCollection}" Height="200"/>
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