Xamarin Android: Why authentication to azure active diretory is not working

Question

Hello everyone my name is Taniguchi

I am trying to authenticate to azure active directory but the code sintaxe is showing an error.

Authenticate interface:

public interface IAuthenticator
{
    Task<AuthenticationResult> Authenticate(string authority, string resource, string clientId, string returnUri);
}

authenticator class:

[assembly: Xamarin.Android.Dependency(typeof(App11.Authenticator))]
public class Authenticator : IAuthenticator
{
    public async Task<AuthenticationResult> Authenticate(string authority, string resource, string clientId, string returnUri)
    {
        var authContext = new AuthenticationContext(authority);
        if (authContext.TokenCache.ReadItems().Count() > 0)
            authContext = new AuthenticationContext(authContext.TokenCache.ReadItems().First().Authority);
        var uri = new Uri(returnUri);

        var platformParams = new PlatformParameters((Activity)Android.Context);
        var authResult = await authContext.AcquireTokenAsync(resource, clientId, uri, platformParams);
        return authResult;
    }
}

where i calling the authentification:

public class MainActivity : AppCompatActivity
{
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);
        SetContentView(Resource.Layout.activity_main);
        Authenticate();
    }

    public async void Authenticate()
    {
        string Nome_Usuario = "taniguchi.sales@ax4b.com";
        string clientId = "2b121ed5-9fe6-4ddf-bdea-9bbe8cd37bd0";
        string authority = "https://login.microsoftonline.com/ax4b.com";
        string returnUri = "https://ax4bdev.crm2.dynamics.com";
        string graphResourceUri = "https://ax4bdev.crm2.dynamics.com";
        var auth = Xamarin.Android.DependencyService.Get<IAuthenticator>();
        var data = await auth.Authenticate(authority, graphResourceUri, clientId, returnUri);
    }

    protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
    {
        base.OnActivityResult(requestCode, resultCode, data);
        AuthenticationAgentContinuationHelper.SetAuthenticationAgentContinuationEventArgs(requestCode, resultCode, data);
    }

The Line:

[assembly: Xamarin.Android.Dependency(typeof(App11.Authenticator))]

is showing the error: Error CS0234 The type or namespace name 'DependencyAttribute' does not exist in the namespace 'Xamarin.Android' (are you missing an assembly reference?)

Answer 1

[assembly: Xamarin.Android.Dependency(typeof(App11.Authenticator))]

DependencyService is usually used in Xamarin.Forms ,but now you are Xamarin.Android project.you dont need IAuthenticator and Authenticator class,you could write the method in your activity directly like (I'm not sure your Authenticate method works，only for the error of Dependency):

private  async void Authenticate()
    {
        string Nome_Usuario = "taniguchi.sales@ax4b.com";
        string clientId = "2b121ed5-9fe6-4ddf-bdea-9bbe8cd37bd0";
        string authority = "https://login.microsoftonline.com/ax4b.com";
        string returnUri = "https://ax4bdev.crm2.dynamics.com";
        string graphResourceUri = "https://ax4bdev.crm2.dynamics.com";
        var data = await Authenticate(authority, graphResourceUri, clientId, returnUri);

    }

    private async Task<AuthenticationResult> Authenticate(string authority, string resource, string clientId, string returnUri)
    {
        var authContext = new AuthenticationContext(authority);
        if (authContext.TokenCache.ReadItems().Count() > 0)
            authContext = new AuthenticationContext(authContext.TokenCache.ReadItems().First().Authority);
        var uri = new Uri(returnUri);

        var platformParams = new PlatformParameters(this);
        var authResult = await authContext.AcquireTokenAsync(resource, clientId, uri, platformParams);
        return authResult;
    }