Updating the Windows and Windows Phone Applications with the new Azure Mobile Service Entities

Updating the Windows and Windows Phone Applications with the new Azure Mobile Service Entities

In my previous post I extended the Azure Mobile Service to include two entities, RealEstateProperty and Inspection. I’m now going to return to the Windows platform projects (ie Windows and Windows Phone) and update them to use these new entities.Rather than duplicate the entity definition I’m going to reuse the entity definition I created previously. Unfortunately, the base class of the two entities is a class called EntityData which is specific to Azure Mobile Service SDK for the full .NET Framework (ie to power the .NET backend services). This means we can simply move these entities into a class library, or better still a PCL, and reference it. Instead we’ll need to make the base class conditional on where the entities are being used – this is a great use for a Shared Project.

We already have a Shared Project which is used to share common code between the Windows platform projects. One option would be to simply reference this project from the service project but this would mean we couldn’t include any shared XAML or Windows platform specific code. Instead I’m going to create a new Shared Project which will be used to contain the entities that are going to be shared across both the Windows platform projects and the service project. To do this I need to download and install the Shared Project Reference Manager which extends Visual Studio to allow for the easy creation and referencing of Shared Projects. After installing the extension I simply add a new project as I would any other project type – right-click the solution node in Solution Explorer and select Add –> New Project. Select the Shared Project and give it a name, in this case will keep it inline with the other Shared Project by naming it RealEstateInspector.Shared.Entities.

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With the Shared Project created, I need to add a reference to the Shared Project to both Windows platform projects and the service project – right-click the References node under the project and select Add Shared Project Reference. The two Windows platform projects should have both shared projects selected, whilst the service project should only reference the new Shared Project.

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Next I need to move my entities out of the service project and into the shared project. I’ll also take this opportunity to change the base class, which as you’ll see will allow us to provide a different base class implementation depending on whether the entities are being compiled into the windows platform projects or the service project.

public class RealEstateProperty : BaseEntityData
{
    public string Address { get; set; }

    public virtual ICollection<Inspection> Inspections { get; set; }
}

public class Inspection : BaseEntityData
{
    public string InspectedBy { get; set; }

    public string RealEstatePropertyId { get; set; }
    public RealEstateProperty RealEstateProperty { get; set; }

}

The BaseEntityData class looks like this:

#if SERVICE
using Microsoft.WindowsAzure.Mobile.Service;
#endif

namespace RealEstateInspector.Shared.Entities
{
    public class BaseEntityData
#if SERVICE
       : EntityData{}
#else
    {
        public string Id { get; set; }
    }
#endif
}

You’ll notice that the BaseEntityData makes use of a compilation symbol to firstly control the base class (ie use the EntityData class if SERVICE is defined) and secondly whether the Id property is defined. The SERVICE symbol isn’t a predefined symbol so I’ll need to define that in my service project. I could have switched the logic to use one of the existing symbols, such as WINDOWS_APP but then if we ever extend this to other platforms, I’d have to modify the logic. It seems better to simply add a SERVICE symbol to the service project. Double-click the Properties node under the service project in Solution Explorer and then open the Build tab. Make sure you select All Configurations before adding SERVICE to the compilation symbols.

image

If I now go to the MainPage.Shared.cs (which I created in an earlier post) where we wrote the initial logic to query the TodoItems from the Mobile Service, I can update the code to instead use either, or both, the new entities we’ve defined:

protected async override void OnNavigatedTo(NavigationEventArgs e)
{
    base.OnNavigatedTo(e);

    var items = await MobileService.GetTable<Inspection>().ToListAsync();
    Debug.WriteLine(items!=null);
}

Whilst I’ve refactored the service code, there’s no reason to publish the new version since we haven’t modified the structure of the entities. However, there should be no harm in doing so if you’d like to keep the service up to date.

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