Using Dependency Services in Xamarin

Introduction

Dependency services in Xamarin allow you to call platform-specific functionality from shared code. This enables you to access native APIs and features that are not directly available through Xamarin.Forms.

Setting Up Dependency Services

To use dependency services, you need to define an interface in your shared code and implement it in the platform-specific projects.

public interface IDeviceInfo
{
    string GetModel();
    string GetVersion();
}

Implementing the Interface

Next, implement the interface in each platform-specific project.

[assembly: Dependency(typeof(DeviceInfoService))]
namespace MyXamarinApp.Droid
{
    public class DeviceInfoService : IDeviceInfo
    {
        public string GetModel()
        {
            return Android.OS.Build.Model;
        }

        public string GetVersion()
        {
            return Android.OS.Build.VERSION.Release;
        }
    }
}

[assembly: Dependency(typeof(DeviceInfoService))]
namespace MyXamarinApp.iOS
{
    public class DeviceInfoService : IDeviceInfo
    {
        public string GetModel()
        {
            return UIKit.UIDevice.CurrentDevice.Model;
        }

        public string GetVersion()
        {
            return UIKit.UIDevice.CurrentDevice.SystemVersion;
        }
    }
}

Using Dependency Services

Finally, use the dependency service in your shared code to call the platform-specific functionality.

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();

        var deviceInfo = DependencyService.Get<IDeviceInfo>();
        modelLabel.Text = deviceInfo.GetModel();
        versionLabel.Text = deviceInfo.GetVersion();
    }
}

Complete Example

Here is the complete example with all the components put together.

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyXamarinApp.MainPage">
    <StackLayout>
        <Label x:Name="modelLabel" Text="Model"
           VerticalOptions="CenterAndExpand" 
           HorizontalOptions="CenterAndExpand" />
        <Label x:Name="versionLabel" Text="Version"
           VerticalOptions="CenterAndExpand" 
           HorizontalOptions="CenterAndExpand" />
    </StackLayout>
</ContentPage>

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();

        var deviceInfo = DependencyService.Get<IDeviceInfo>();
        modelLabel.Text = deviceInfo.GetModel();
        versionLabel.Text = deviceInfo.GetVersion();
    }
}

public interface IDeviceInfo
{
    string GetModel();
    string GetVersion();
}

[assembly: Dependency(typeof(DeviceInfoService))]
namespace MyXamarinApp.Droid
{
    public class DeviceInfoService : IDeviceInfo
    {
        public string GetModel()
        {
            return Android.OS.Build.Model;
        }

        public string GetVersion()
        {
            return Android.OS.Build.VERSION.Release;
        }
    }
}

[assembly: Dependency(typeof(DeviceInfoService))]
namespace MyXamarinApp.iOS
{
    public class DeviceInfoService : IDeviceInfo
    {
        public string GetModel()
        {
            return UIKit.UIDevice.CurrentDevice.Model;
        }

        public string GetVersion()
        {
            return UIKit.UIDevice.CurrentDevice.SystemVersion;
        }
    }
}