In Xamarin Forms, there is a limitation for fingerprint and face id, it will not store in your application database for security reasons. It will be store in your mobile hardware and that is the OS level data. Not all android devices are supported face id detection some android devices support this feature.

For using the face id or fingerprint or other bios metric so firstly we need to add permissions for both Android and iOS.

Now, let’s start with the implementation.

Open Visual Studio and select Xamarin project.

Image: Create a Xamarin project

After selecting Xamarin forms, select Blank App for Android and iOS platforms.

Image: Select template and platform.

When we started a project first we need to add the NuGet package, for adding package Go to Tools -> NuGet Package Manager -> Manage NuGet Packages for a solution and add Plugin.Fingerprint Package.

When we work on bio-metric we need to give permission for Android and iOS.

Open AndroidManifest.xml and add the below permission.

Now, create a file in a shared project.

FingerPrintService.cs

using System;
using System.Threading.Tasks;

namespace FingerprintExample
{
    public interface FingerPrintService
    {
        String GetType();
        Task UserID();
        bool fingerprintEnabled();
    }
}
				

Now, open the Android project and create a class.

FPService.cs

After that, we create a fingerprint handler to handle the fingerprint callback.

FingerPrintHandler.cs

				using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Support.V4.Hardware.Fingerprint;
using Android.Views;
using Android.Widget;
using Xamarin.Forms;

namespace FingerprintExample.Droid
{
    public class FingerPrintHandler : FingerprintManagerCompat.AuthenticationCallback
    {
        private Context mainActivity;

        public bool AuthResult;
        public FingerPrintHandler(Context mainActivity)
        {
            this.mainActivity = mainActivity;
        }
        internal void Startprog(FingerprintManagerCompat fingerprintManager, FingerprintManagerCompat.CryptoObject cryptoObject)
        {
            CancellationSignal cancellationSignal = new CancellationSignal();
                    }
        public override void OnAuthenticationFailed()
        {
            FPService.IsAutSucess = false;
            Toast.MakeText(mainActivity, "Fingerprint Authentication failed!", ToastLength.Long).Show();
            MessagingCenter.Send("Auth", "Fail");
        }
        public override void OnAuthenticationSucceeded(FingerprintManagerCompat.AuthenticationResult result)
        {
            FPService.IsAutSucess = true;
            Toast.MakeText(mainActivity, "Fingerprint Authentication Success", ToastLength.Long).Show();
            MessagingCenter.Send("Auth", "Success");
        }
    }
}