Question

I have the requirement in my WP7 application to display pushpins on a bing map from multiple data sources and I am not sure of the best way to do this.

So for example it would be something like this, I receive from a web service a list of people, a list of buildings, a list of POIs etc. I would need to display these individually in their own views but also display them on a map with different images for each type.

I am trying to use a MVVM approach so have a class for a Person, class for a building and so on, each one of these has a location. I then have an ObservableCollection for each of these types and so using data binding it is easy enough to do a View for each of these.

At the moment I only have one ViewModel but my first thought is that I think I should really have one ViewModel per type. So PersonViewModel, BuildingViewModel here? However a Map View would then need to take information from each of these views and I am no sure how you bind a view to multiple ViewModels like this or even if that is sensible.

MapItemsControl also only seems to be able to bind to one thing so how can I bind it to multiple different data sources like this? I thought I could create a simple pushpin class but that would then mean having the data for each type duplicated and I eventually want to be able to click on the pushpins to display the details for the pin so wanted to keep the types separate

Any pointers on a way forward much appreciated

Answer 1

Using a MapItemsControl is as you say, the way to do it. And it’s very easy. What you want is a ViewModel with a ObservableCollection for each of your types, as you say you already have.

So I guess your problem is that you don’t understand how to use Styles and ItemTemplates.

If what you want, is to have the same style for each of the different types, then simply define a common ItemTemplate that you apply to each MapItemsControl.ItemTemplate. Likewise you can define a custom style that you apply to each Pushpin globally, if what’s what you want.

<Grid.Resources>
    <DataTemplate x:Name="PushpinItemTemplate">
        <maps:Pushpin Location="{Binding Location}" Tap="Pushpin_Tap" Style="{StaticResource PushpinStyle}" />
    </DataTemplate>
</Grid.Resources>

...

<maps:Map>
    <maps:MapLayer>
        <maps:MapItemsControl ItemsSource="{Binding People}" ItemTemplate="{StaticResource PushpinItemTemplate}" />
        <maps:MapItemsControl ItemsSource="{Binding Buildings}" ItemTemplate="{StaticResource PushpinItemTemplate}" />
    </maps:MapLayer>
</maps:Map>