I'm working with C# xamarin forms android and I'm trying to get the IMEI number. I've been searching about it and everything I found doesn't works. Now I'm trying with this code but again, Doesn't works.
Errors:

1. The name settings does not exist in the current context.
2. The name Forms does not exist in the current context.
   C# code:

[assembly: Xamarin.Forms.Dependency(typeof(UniqueIdAndroid))]
namespace AppMobile.Models
{
    public class UniqueIdAndroid
    {
        public string GetIdentifier()
        {
            return Settings.Secure.GetString(Forms.Context.ContentResolver, Settings.Secure.AndroidId);
        }
    }
}

Somebody knows how could I resolve this or knows other solution? Thank you very much!

UPDATE 1

c# code:

using Android.OS;
using AppMobile.Models;
using System;
using System.Collections.Generic;
using System.Text;
using static Android.Provider.Settings;
using Android.Provider;
using Xamarin.Forms;

    [assembly: Xamarin.Forms.Dependency(typeof(UniqueIdAndroid))]
    namespace AppMobile.Models
    {
        public class UniqueIdAndroid : IDevice
        {
            public string GetIdentifier()
            {
                return Settings.Secure.GetString(Forms.Context.ContentResolver, Settings.Secure.AndroidId);
            }
        }
    }

I have added the IDevice interface that I don't know really what it should be and I fixed the settings problem with using Android.Provider; . this link shows that I have to call with this:

string deviceIdentifier = DependencyService.Get<IDevice>().GetIdentifier();

But i don't understand how to implement IDevice interface.
Someone can help me? Thank you very much!

UPDATE 2

so, now I can use the function.
C# code:

using Android.OS;
using AppMobile.Models;
using System;
using System.Collections.Generic;
using System.Text;
using static Android.Provider.Settings;
using Android.Provider;
using Xamarin.Forms;
using Android.Content;

[assembly: Xamarin.Forms.Dependency(typeof(UniqueIdAndroid))]
namespace AppMobile.Models
{
    public class UniqueIdAndroid
    {
        
        public string GetIdentifier()
        {
            //return Settings.Secure.GetString(Forms.Context.ContentResolver, Settings.Secure.AndroidId);
            
            return Settings.Secure.GetString(Android.App.Application.Context.ContentResolver, Settings.Secure.AndroidId);
        }
        
    }
}

My problem is that this doesn't give me the IMEI. Insted it gives me the ID of the phone, ¿is there some way to get the IMEI string? Thank you very much!