# Integrating DI Containers

Components Context can store global level variables, like for example service container references. In the following sample we'll see how to get access to services inside a component.

Create a new Xamarin Forms project using the Hellp World [tutorial](/reactorui/guide/hello-world-sample.md) (called for example RXAppContainer), add a new .NET standard project (for example called RxAppContainer.Services) and add a reference to it from the XF project, finally remove the MainPage.xaml.

Create a simple service with a method that add 2 numbers in the RxAppContainer.Services project:

```csharp
public interface ICalcService
{
    double Add(double x, double y);
}

public class CalcService : ICalcService
{
    public double Add(double x, double y) => x + y;
}
```

Than create a component in the XF project like the following:

```csharp
public class MainPageState : IState
{
    public double X { get; set; }
    public double Y { get; set; }
    public double Result { get; set; }
}

public class MainPage : RxComponent<MainPageState>
{
    public override VisualNode Render()
    {
        return new RxNavigationPage()
        {
            new RxContentPage()
            { 
                new RxStackLayout()
                {
                    NumericEntry(State.X, v => SetState(s => s.X = v)),
                    new RxLabel(" + ")
                        .FontSize(NamedSize.Large)
                        .VCenter(),
                    NumericEntry(State.Y, v => SetState(s => s.Y = v)),
                    new RxButton(" + ")
                        .OnClick(OnAdd),
                    new RxLabel(State.Result.ToString())
                        .FontSize(NamedSize.Large)
                        .VCenter()
                }
                .Spacing(10)
                .VCenter()
                .HCenter()
                .WithHorizontalOrientation()
            }
            .Title("DI Container Sample")
        };
    }

    private void OnAdd()
    {

    }

    private RxEntry NumericEntry(double value, Action<double> onSet)
        => new RxEntry(value.ToString())
            .OnAfterTextChanged(s => onSet(double.Parse(s)))
            .Keyboard(Keyboard.Numeric)
            .VCenter();
}

```

Solution should look like this:

![Sample demonstrating DI integration ](/files/-M4yPpICd64qypl7ClPF)

In this sample I'm going to use the Microsoft Dependency Injection package to collect and provide services to the app. \
Add the Microsoft.Extensions.DependencyInjection package to the XF project with the following command or thru Visual Studio tool window:

```csharp
Install-Package Microsoft.Extensions.DependencyInjection
```

We now need to register our CalcService with it in the App.xaml.cs:

```csharp
public App()
{
    InitializeComponent();

    var serviceCollection = new ServiceCollection();
    serviceCollection.AddTransient<ICalcService, CalcService>();

    _app = RxApplication.Create<MainPage>(this)
        .WithContext("ServiceProvider", serviceCollection.BuildServiceProvider())
        .WithHotReload();
}
```

`WithContext()` extension method allows us to set application root component context.

Now let's run the app and modify the component `OnAdd()` method so that it uses the `ICalcService`

```csharp
var serviceProvider = (IServiceProvider)Context["ServiceProvider"];
var calcService = serviceProvider.GetService<ICalcService>();
SetState(s => s.Result = calcService.Add(State.X, State.Y));
```

![Access Context inside a component to get a reference to a service](/files/-M4yRMCTORl2jOG-VuAJ)

**NOTE**: Services must be located in a different project if you want them working with hot reload.


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