How do I use a Unity IoC container with Template10?
I have an app based on Template10 and want to handle my dependency injection using IoC. I am leaning toward using Unity for this. My app is divided into three assemblies:
I have these questions:
I have read a lot about DI and IoC but I need to know how to apply all the theory in practice, specifically in Template10.
The code to register:
// where should I put this code?
var container = new UnityContainer();
container.RegisterType<ISettingsService, RoamingSettingsService);
And then the code to retrieve the instances:
var container = ???
var settings = container.Resolve<ISettingsService>();
I not familiar with Unity Container .
My example is using LightInject , you can apply similar concept using Unity . To enable DI on ViewModel you need to override ResolveForPage on App.xaml.cs on your project.
public class MainPageViewModel : ViewModelBase
{
ISettingsService _setting;
public MainPageViewModel(ISettingsService setting)
{
_setting = setting;
}
}
[Bindable]
sealed partial class App : Template10.Common.BootStrapper
{
internal static ServiceContainer Container;
public App()
{
InitializeComponent();
}
public override async Task OnInitializeAsync(IActivatedEventArgs args)
{
if(Container == null)
Container = new ServiceContainer();
Container.Register<INavigable, MainPageViewModel>(typeof(MainPage).FullName);
Container.Register<ISettingsService, RoamingSettingsService>();
// other initialization code here
await Task.CompletedTask;
}
public override INavigable ResolveForPage(Page page, NavigationService navigationService)
{
return Container.GetInstance<INavigable>(page.GetType().FullName);
}
}
Template10 will automaticaly set DataContext to MainPageViewModel , if you want to use {x:bind} on MainPage.xaml.cs :
public class MainPage : Page
{
MainPageViewModel _viewModel;
public MainPageViewModel ViewModel
{
get { return _viewModel??(_viewModel = (MainPageViewModel)this.DataContext); }
}
}
here is a small example how i use Unity and Template 10.
1. Create a ViewModel
I also created a DataService class to create a list of people. Take a look at the [Dependency] annotation.
public class UnityViewModel : ViewModelBase
{
public string HelloMessage { get; }
[Dependency]
public IDataService DataService { get; set; }
private IEnumerable<Person> people;
public IEnumerable<Person> People
{
get { return people; }
set { this.Set(ref people, value); }
}
public UnityViewModel()
{
HelloMessage = "Hello !";
}
public override async Task OnNavigatedToAsync(object parameter, NavigationMode mode,
IDictionary<string, object> suspensionState)
{
await Task.CompletedTask;
People = DataService.GetPeople();
}
}
2. Create a Class to create and fill your UnityContainer
Add the UnityViewModel and the DataService to the unityContainer. Create a property to resolve the UnityViewModel.
public class UnitiyLocator
{
private static readonly UnityContainer unityContainer;
static UnitiyLocator()
{
unityContainer = new UnityContainer();
unityContainer.RegisterType<UnityViewModel>();
unityContainer.RegisterType<IDataService, RuntimeDataService>();
}
public UnityViewModel UnityViewModel => unityContainer.Resolve<UnityViewModel>();
}
3. Add the UnityLocator to your app.xaml
<common:BootStrapper x:Class="Template10UWP.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:common="using:Template10.Common"
xmlns:mvvmLightIoc="using:Template10UWP.Examples.MvvmLightIoc"
xmlns:unity="using:Template10UWP.Examples.Unity">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="StylesCustom.xaml" />
<ResourceDictionary>
<unity:UnitiyLocator x:Key="UnityLocator" />
</ResourceDictionary>
</ResourceDictionary.MergedDictionaries>
<!-- custom resources go here -->
</ResourceDictionary>
</Application.Resources>
4. Create the page
Use the UnityLocator to set the UnityViewModel as DataContext and bind the properties to the controls
<Page
x:Class="Template10UWP.Examples.Unity.UnityMainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Template10UWP.Examples.Unity"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
DataContext="{Binding Source={StaticResource UnityLocator}, Path=UnityViewModel}"
mc:Ignorable="d">
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<TextBlock Text="{Binding HelloMessage}" HorizontalAlignment="Center"
VerticalAlignment="Center" />
<ListBox Grid.Row="1" ItemsSource="{Binding People}" DisplayMemberPath="FullName">
</ListBox>
</Grid>
The DataService will be injected automatically when the page resolves the UnityViewModel.
Now to your questions
This depends on how the projects depend on each other. I am not sure what´s the best solution, but i think i would try to use one UnityContainer and place it in the core library.
I hope my examples answered this question
I hope my examples answered this question