Static and dynamic panorama items in a panorama wp7 mvvm

Question

Here is my situation.

ViewModelA {  
    ObservableCollection<Items> ItemsA  
    ObservableCollection<ViewModelB> ViewModelBs
}

View A with the datacontext set to ViewModel A ViewA has a panorama with a listbox, panels, textblocks etc with the items source for the listbox bound to ItemsA

I want to add other panorama items at runtime to the panorama control with a commond data template (listbox, textblock...etc).. Each panorama item will be bound at run time to each ViewModelB in the ViewModelBs collection.

I am not oppose to doing some codebehind stuff for this as I am not a strict mvvm purist.. but the solution could be elegant if I could specify control and data templates and make this work. I am kind of new to wpf/xaml and trying to break in to those technologies by writing a wp7 app.. using the mvvm light framework.. Eventually, i want my dynamically generated panorama items/list box content fire off relay commands on the viewmodel they are being bound to...

Here is some code snippet that i tried unsuccessfully to work. Hope it provides some idea..

<phone:PhoneApplicationPage.Resources>
    <Style x:Key="PanoramaItemStyle" TargetType="ContentControl">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="ContentControl">
                    <Grid x:Name="ContentGrid">
                        <controls:PanoramaItem x:Name="ItemLocationPanoramaItem" Header="{Binding TagName}">
                            <StackPanel >
                                <ListBox  x:Name="ItemLocatorsList" ItemsSource="{Binding ItemLocators}" Height="496" SelectedItem="{Binding SelectedItemLocation, Mode=TwoWay}" >
                                    <Custom:Interaction.Triggers>
                                        <Custom:EventTrigger EventName="SelectionChanged">
                                            <GalaSoft_MvvmLight_Command:EventToCommand x:Name="SelectionChangedEvent" Command="{Binding RelativeSource={RelativeSource TemplatedParent},Path=DataContext.GoToEditItemLocatorCommand}" PassEventArgsToCommand="True"/>
                                        </Custom:EventTrigger>
                                    </Custom:Interaction.Triggers>
                                    <ListBox.ItemsPanel>
                                        <ItemsPanelTemplate >
                                            <StackPanel Orientation="Vertical"  ScrollViewer.VerticalScrollBarVisibility="Auto" />
                                        </ItemsPanelTemplate>
                                    </ListBox.ItemsPanel>
                                    <ListBox.ItemTemplate>
                                        <DataTemplate>
                                            <StackPanel> 
                                                    <StackPanel Orientation="Horizontal" Margin="0,0,0,17">
                                                        <StackPanel Width="311">
                                                            <TextBlock Text="{Binding Path=Item.Name}" TextWrapping="Wrap" Style="{StaticResource PhoneTextLargeStyle}"/>
                                                            <TextBlock Text="{Binding Path=Location.Description}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}"/>
                                                        </StackPanel>
                                                    </StackPanel> 
                                            </StackPanel>
                                        </DataTemplate>
                                    </ListBox.ItemTemplate>
                                </ListBox>
                            </StackPanel>
                        </controls:PanoramaItem>
                        <ContentPresenter/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Setter Property="Foreground" Value="White"/>
    </Style> 
</phone:PhoneApplicationPage.Resources>

Codebehind: private LocationGroupsViewModel viewModel = null;

    public LocationGroups()
    {
        InitializeComponent(); 
        LocationGroupsPanaroma.DefaultItem = LocationGroupsPanaroma.Items[0];
         viewModel = this.DataContext as LocationGroupsViewModel;
         CreateDynamicPanaromaItems();
    }


    private void CreateDynamicPanaromaItems()
    {
        foreach (Model.LocationGroup group in viewModel.LocationGroups)
        {
            if (group.TotalItems > 0)
            {
                PanoramaItem pi = new PanoramaItem();
                pi.Header = group.Name;
                pi.Orientation = System.Windows.Controls.Orientation.Horizontal;
                ItemLocationListViewModel itemLocationViewModel = viewModel[group.LocationGroupId];
                pi.DataContext = itemLocationViewModel;
                pi.Style = Resources["PanoramaItemStyle"] as Style;
                LocationGroupsPanaroma.Items.Add(pi);

            }
        }

    }

Edit

ViewModel A has

Items collection

Collection of ViewModelBs

panaroma data context set to viewmodelA

panaroma item - Statitically created in xaml to some Items collection in ViewModelA

    This pan item has a list box



panaroma items --- to be bound to collection of viewmodelbs

    These pan items should each have a listbox which is selectable
                  and  bound to some collection in View Model B and fires commands on    selection         changed to viewModelB. Currently using the galasoft eventtocommand to hook the selection changed on the
    list box to a relay command. The problem is that this eventtommand should have the viewmodel as its data context and the not the collection (bound to the listbox) within viewmodel. 

Answer 1

OK, finally got time to answer the question. The proposed solution does not require any code behind and only relys on MVVM concepts and data binding.

Conceptionally the Panorama control is an ItemPresenter (it inherits from ItemsPresenter), i.e. you can bind the ItemsSource to a list that contains items that repesent your PanoramaItems.

To render your PanoramaItem you will have to provide templates for Panorama.HeaderTemplate and Panorama.ItemTemplate. The DataContext inside the templates is the ViewModel that represents your PanoramaItem. If this ViewModel contains an item list you now can use it to generate the ListBoxes you were looking for.

And here is the sample ...

ViewModelLocator.cs

using GalaSoft.MvvmLight;

namespace WP7Test.ViewModel
{
    public class ViewModelLocator
    {
        private static MainViewModel _main;

        public ViewModelLocator()
        {
    if (ViewModelBase.IsInDesignModeStatic) {
        // Create design time services and viewmodels
    } else {
        // Create run time services and view models
    }
            _main = new MainViewModel();
        }

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance",
            "CA1822:MarkMembersAsStatic",
            Justification = "This non-static member is needed for data binding purposes.")]
        public MainViewModel Main
        {
            get
            {
                return _main;
            }
        }
    }
}

MainViewModel.cs

public class MainViewModel : ViewModelBase
{
    public MainViewModel()
    {
        this.Items = new ObservableCollection<ItemViewModel>();

        if (IsInDesignMode) {
            // Code runs in Blend --> create design time data.
        } else {
            // Code runs "for real"
        }
        this.LoadData();
    }

    #region [Items]

    public const string ItemsPropertyName = "Items";

    private ObservableCollection<ItemViewModel> _items = default(ObservableCollection<ItemViewModel>);

    public ObservableCollection<ItemViewModel> Items {
        get {
            return _items;
        }
        private set {
            if (_items == value) {
                return;
            }

            var oldValue = _items;
            _items = value;

            RaisePropertyChanged(ItemsPropertyName);
        }
    }

    #endregion

    private void LoadData() {
        this.Items.Add(new ItemViewModel() { LineOne = "runtime one", LineTwo = "Maecenas praesent accumsan bibendum", LineThree = "Facilisi faucibus habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime two", LineTwo = "Dictumst eleifend facilisi faucibus", LineThree = "Suscipit torquent ultrices vehicula volutpat maecenas praesent accumsan bibendum dictumst eleifend facilisi faucibus" });
        this.Items.Add(new ItemViewModel() { LineOne = "runtime three", LineTwo = "Habitant inceptos interdum lobortis", LineThree = "Habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu suscipit torquent" });

        foreach (var item in Items) {
            for (int i = 0; i < 5; ++i)
                item.Items.Add(new ItemViewModel() { LineOne = "Item " + i, LineTwo = "Maecenas praesent accumsan bibendum" });
        }
    }
}

ItemViewModel.cs

public class ItemViewModel : ViewModelBase
{
    public ItemViewModel() {
        this.Items = new ObservableCollection<ItemViewModel>();

        if (IsInDesignMode) {
            // Code runs in Blend --> create design time data.
        } else {
            // Code runs "for real": Connect to service, etc...
        }
    }

    public override void Cleanup() {
        // Clean own resources if needed

        base.Cleanup();
    }

    #region [LineOne]

    public const string LineOnePropertyName = "LineOne";

    private string _lineOne = default(string);

    public string LineOne {
        get {
            return _lineOne;
        }

        set {
            if (_lineOne == value) {
                return;
            }

            var oldValue = _lineOne;
            _lineOne = value;
            RaisePropertyChanged(LineOnePropertyName);
        }
    }

    #endregion

    #region [LineTwo]

    public const string LineTwoPropertyName = "LineTwo";

    private string _lineTwo = default(string);

    public string LineTwo {
        get {
            return _lineTwo;
        }

        set {
            if (_lineTwo == value) {
                return;
            }

            var oldValue = _lineTwo;
            _lineTwo = value;

            RaisePropertyChanged(LineTwoPropertyName);
        }
    }

    #endregion

    #region [LineThree]

    public const string LineThreePropertyName = "LineThree";

    private string _lineThree = default(string);

    public string LineThree {
        get {
            return _lineThree;
        }

        set {
            if (_lineThree == value) {
                return;
            }

            var oldValue = _lineThree;
            _lineThree = value;
            RaisePropertyChanged(LineThreePropertyName);
        }
    }

    #endregion

    #region [Items]

    public const string ItemsPropertyName = "Items";

    private ObservableCollection<ItemViewModel> _items = default(ObservableCollection<ItemViewModel>);

    public ObservableCollection<ItemViewModel> Items {
        get {
            return _items;
        }
        private set {
            if (_items == value) {
                return;
            }

            var oldValue = _items;
            _items = value;
            RaisePropertyChanged(ItemsPropertyName);
        }
    }

    #endregion
}

MainPage.xaml

<phone:PhoneApplicationPage 
    x:Class="WP7Test.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:controls="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="800" 
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait"  Orientation="Portrait"
    shell:SystemTray.IsVisible="False">

    <!--LayoutRoot is the root grid where all page content is placed-->
    <Grid x:Name="LayoutRoot" Background="Transparent" DataContext="{Binding Main, Source={StaticResource Locator}}">
        <controls:Panorama Title="my application" ItemsSource="{Binding Items}">
            <controls:Panorama.Background>
                <ImageBrush ImageSource="PanoramaBackground.png"/>
            </controls:Panorama.Background>
            <controls:Panorama.HeaderTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding LineOne}"/>
                </DataTemplate>
            </controls:Panorama.HeaderTemplate>
            <controls:Panorama.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <Border BorderThickness="0,0,0,1" BorderBrush="White">
                            <TextBlock Text="{Binding LineTwo}" FontSize="28" TextWrapping="Wrap"/>
                        </Border>
                        <Border BorderThickness="0,0,0,1" Margin="0,20" BorderBrush="White">
                            <TextBlock Text="{Binding LineThree}" TextWrapping="Wrap"/>
                        </Border>
                        <ListBox ItemsSource="{Binding Items}">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <StackPanel>
                                        <TextBlock Text="{Binding LineOne}" FontSize="24"/>
                                        <TextBlock Text="{Binding LineTwo}" FontSize="18" Margin="24,0,0,5"/>
                                    </StackPanel>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>
                    </StackPanel>
                </DataTemplate>
            </controls:Panorama.ItemTemplate>
        </controls:Panorama>
    </Grid>
    <!--Panorama-based applications should not show an ApplicationBar-->
</phone:PhoneApplicationPage>

Edit - adding additional first panel

Finally I understand what you trying to achive! However, you still need no code behind to do it! You just need a template ... for this Blend does help you as it lets you extract a template for a exiting control ... ok, here are the changes.

First I added a new property to the MainViewModel to show some data:

#region [MainPageProperty]

public const string MainPagePropertyPropertyName = "MainPageProperty";
private string _mainPageProperty = "Facilisi faucibus habitant inceptos interdum lobortis nascetur pharetra placerat pulvinar sagittis senectus sociosqu";

public string MainPageProperty {
    get {
        return _mainPageProperty;
    }
    set {
        if (_mainPageProperty == value) {
            return;
        }

        _mainPageProperty = value;
        RaisePropertyChanged(MainPagePropertyPropertyName);
    }
}

#endregion

Then I used Blend to get the template for the Panorama control and inserted it into the controls:Panorama element.

<controls:Panorama.Template>
    <ControlTemplate TargetType="controls:Panorama">
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="auto"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <controlsPrimitives:PanningBackgroundLayer x:Name="BackgroundLayer" HorizontalAlignment="Left" Grid.RowSpan="2">
                <Border x:Name="background" Background="{TemplateBinding Background}" CacheMode="BitmapCache"/>
            </controlsPrimitives:PanningBackgroundLayer>
            <controlsPrimitives:PanningTitleLayer x:Name="TitleLayer" CacheMode="BitmapCache" ContentTemplate="{TemplateBinding TitleTemplate}" Content="{TemplateBinding Title}" FontSize="187" FontFamily="{StaticResource PhoneFontFamilyLight}" HorizontalAlignment="Left" Margin="10,-76,0,9" Grid.Row="0"/>
            <controlsPrimitives:PanningLayer x:Name="ItemsLayer" HorizontalAlignment="Left" Grid.Row="1">
                <StackPanel Orientation="Horizontal">
                    <controls:PanoramaItem Header="Main panel" Width="432">
                        <TextBlock Text="{Binding ElementName=LayoutRoot, Path=DataContext.MainPageProperty}" TextWrapping="Wrap"/>
                    </controls:PanoramaItem>
                    <ItemsPresenter x:Name="items"/>
                </StackPanel>
            </controlsPrimitives:PanningLayer>
        </Grid>
    </ControlTemplate>
</controls:Panorama.Template>

There are two tricks here, first I inserted a StacPanel to have allow for more than one element underneath the controlPrimitives:PanningLayer with the name ItemsPanel. Into this StackPanel I moved the ItemsPresenter and added another PanoramaItem. One thing that is important, though, is to set the Width property of the PanoramaItem, as otherwise the panel will extend to the room that is needed.

The other trick is that in order to get access to the DataContext I had to use the ElementName in the Binding.

Hope this shows the power of MVVM and Templating!