Having problem to get GPS

Hi,

I tried the tutorial GPS from this link: http://docs.xamarin.com/recipes/android/os_device_resources/gps/get_current_device_location

using System; using Android.App; using Android.Content; using Android.Runtime; using Android.Views; using Android.Widget; using Android.OS;

//-- added these

using Android.Locations; using System.Collections.Generic; using System.Threading; using System.Text;

namespace GetLocation {

[Activity(Label = "Get Location", MainLauncher = true, Icon = "@drawable/icon")]
public class Activity1 : Activity, ILocationListener
{

    //int count = 1;

    private Location _currentLocation;
    private LocationManager _locationManager;
    private TextView _locationText;
    private TextView _addressText;


    protected override void OnCreate (Bundle bundle)
    {
        base.OnCreate (bundle);

        SetContentView(Resource.Layout.Main);

        _addressText = FindViewById(Resource.Id.address_text);
        _locationText = FindViewById(Resource.Id.location_text);
        FindViewById(Resource.Id.get_address_button).Click += AddressButton_OnClick;

        InitializeLocationManager();       

    }


    //public void OnLocationChanged(Location location) {}
    public void OnProviderDisabled(string provider) {}
    public void OnProviderEnabled(string provider) {}
    public void OnStatusChanged(string provider, Availability status, Bundle extras) {}


    private void InitializeLocationManager()
    {
        _locationManager = (LocationManager) GetSystemService(LocationService);

        var criteriaForLocationService = new Criteria
        {
            Accuracy = Accuracy.Fine
        };

        var acceptableLocationProviders = _locationManager.GetProviders(criteriaForLocationService, true);


        if (acceptableLocationProviders.Any())
        {
            _locationProvider = acceptableLocationProviders.First();

        }
        else

        {
            _locationProvider = String.Empty;
        }

    }



    protected override void OnResume()
    {

        base.OnResume();
        _locationManager.RequestLocationUpdates(_locationProvider, 0, 0, this);
    }



    protected override void OnPause()
    {
        base.OnPause();
        _locationManager.RemoveUpdates(this);
    }



    private void AddressButton_OnClick(object sender, EventArgs eventArgs)
    {

        if (_currentLocation == null)
        {
            _addressText.Text = "Can't determine the current location.";
            return;
        }

        new Thread(() =>

                   {

            var addressText = "Unable to find a location.";
            var geocoder = new Geocoder(this);
            var addressList = geocoder.GetFromLocation(_currentLocation.Latitude, _currentLocation.Longitude, 50);
            var address = addressList.FirstOrDefault();

            if (address != null)

            {
                var deviceLocation = new StringBuilder();
                for (var i = 0; i  { _addressText.Text = addressText; });
        }).Start();

    }



    public void OnLocationChanged(Location location)

    {
        _currentLocation = location;

        if (_currentLocation == null)

        {
            _locationText.Text = "Unable to determine your location.";
        }
        else
        {
            _locationText.Text = String.Format("{0},{1}", _currentLocation.Latitude, _currentLocation.Longitude);
        }
    }
}

}

How to solve these problems:

Error messages

1)Error CS1061: 'System.Collections.Generic.IList' does not contain a definition for 'Any' and no extension method 'Any' accepting a first argument of type 'System.Collections.Generic.IList' could be found (are you missing a using directive or an assembly reference?) (CS1061) (GetLocation)

2)Error CS0103: The name '_locationProvider' does not exist in the current context (CS0103) (GetLocation)

3)Error CS1061: 'System.Collections.Generic.IList' does not contain a definition for 'First' and no extension method 'First' accepting a first argument of type 'System.Collections.Generic.IList' could be found (are you missing a using directive or an assembly reference?) (CS1061) (GetLocation)

4)Error CS0103: The name '_locationProvider' does not exist in the current context (CS0103) (GetLocation)

5) Error CS1061: 'System.Collections.Generic.IList' does not contain a definition for 'FirstOrDefault' and no extension method 'FirstOrDefault' accepting a first argument of type 'System.Collections.Generic.IList' could be found (are you missing a using directive or an assembly reference?) (CS1061) (GetLocation)

6) Does it matter if File name is MainActivity.cs and Activity Class is called:

public class Activity1 : Activity, ILocationListener

For problem 1 to 5 , I think I need to add DLL for System.Core , system.XML, How to I add these in Xamarin Studio ?

Thanks