How to create implement grouped checkbox on action menu xamarin android?

Action_menu

<?xml version="1.0" encoding="utf-8" ?> 
<menu xmlns:android="http://schemas.android.com/apk/res/android">

 <item
      android:id="@+id/menu_share"
      android:icon="@drawable/ic_search_white_24dp"
      android:showAsAction="ifRoom"
      android:title="Search"

      />

  <item
      android:id="@+id/menu_settings"
      android:showAsAction="never"
      android:orderInCategory="100"
      android:title="Setting"
      />
      <group android:checkableBehavior="single">
        <item android:id="@+id/selecta"
            android:title="Top 50"
            android:checked="true"
            android:actionViewClass="android.widget.checkbox"
            android:showAsAction="always"/>
        <item android:id="@+id/selectb"
            android:title="New &amp; hot"
            android:actionViewClass="android.widget.checkbox"
            android:showAsAction="always"/>
      </group>

</menu>

public override bool OnOptionsItemSelected (IMenuItem item) 
        {
            switch (item.ItemId) 
            {
            case Android.Resource.Id.Home:
                drawerLayout.OpenDrawer (Android.Support.V4.View.GravityCompat.Start);
                return true;
            case Android.Resource.Id.selecta:
                item.SetChecked (true);
                return true;
            case Android.Resource.Id.selectb:
                item.SetChecked (true);
                return true;
            }
            return base.OnOptionsItemSelected (item);
        }

        // Add options menu on toolbar


        public override bool OnCreateOptionsMenu(Android.Views.IMenu menu)
        {
            MenuInflater.Inflate (Resource.Menu.Action_menu, menu);
            return base.OnCreateOptionsMenu (menu);
        }

I want them such as below picture

I've a problem when i was adding Check box on Action Bar, it is not showing Check box on Action Bar

• Errors: selecta,b does not contain a definition for ....
• It don't see any id into Action_menu.xml