MyPickeriOS.cs

using VisualTest.iOS;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;


[assembly: ExportRenderer(typeof(Xamarin.Forms.Picker), typeof(MyPicker), new[] { typeof(VisualTest.TestVisual) })]


namespace VisualTest.iOS
{
    public class MyPicker : PickerRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
        {
            base.OnElementChanged(e);

            Control.BackgroundColor = Xamarin.Forms.Color.Yellow.ToUIColor();
        }
    }
}