XamarinでPickerにEnumをバインド

BindEnum.cs

namespace TaxPon.View.Themes
{
    public enum ThemeType
    {
        Dark,
        Light,
    }
}

EnumBindablePickerView.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="TaxPon.View.SettingPage"
             xmlns:m="clr-namespace:TaxPon.Model"
             xmlns:c="clr-namespace:TaxPon.View.Converter"
             xmlns:vm="clr-namespace:TaxPon.ViewModel"
             Title="EnumBindablePicker">
    <ContentPage.Icon>
    </ContentPage.Icon>
    <ContentPage.Resources>
        <ResourceDictionary>
            <c:IntEnumConverter x:Key="IntEnum"/>
        </ResourceDictionary>
    </ContentPage.Resources>
    <ContentPage.BindingContext>
        <vm:SettingViewModel/>
    </ContentPage.BindingContext>
    <ContentPage.Content>
        <StackLayout>
            <StackLayout Orientation = "Horizontal"  Margin="10, 0, 10, 0">
                <Label Text = "EnumPicker" VerticalTextAlignment="Center"/>
                <Picker ItemsSource="{Binding Themes}" SelectedIndex="{Binding SelectedTheme.Value, Converter={StaticResource IntEnum}, Mode=TwoWay}" VerticalOptions="End" HorizontalOptions="CenterAndExpand"/>
            </StackLayout>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

EnumBindablePickerViewModel.cs

using Reactive.Bindings;
using Reactive.Bindings.Extensions;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using TaxPon.Model;
using TaxPon.View.Themes;
using Xamarin.Forms;

namespace TaxPon.ViewModel
{
    public class SettingViewModel : IDisposable
    {
        public ReactiveProperty<ThemeType> SelectedTheme { get; }

        private CompositeDisposable Disposable { get; } = new CompositeDisposable();

        public List<string> Themes { get; } = Enum.GetNames(typeof(ThemeType)).ToList();

        public SettingViewModel()
        {
            //Enum
            this.SelectedTheme = new ReactiveProperty<ThemeType>();
                .AddTo(this.Disposable);

            //Picker変更
            this.SelectedTheme.ObserveProperty(x => x.Value)
                .Subscribe(x => { //ここにPickerの選択が変更されたときの処理を書く
                  Console.WriteLine(x);
                })
                .AddTo(this.Disposable);
        }

        public void Dispose()
        {
            this.Disposable.Dispose();
        }
    }
}

IntEnumConverter.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text;
using Xamarin.Forms;

namespace TaxPon.View.Converter
{
    public class IntEnumConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is Enum)
            {
                return (int)value;
            }
            return 0;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is int)
            {
                return Enum.ToObject(targetType, value);
            }
            return 0;
        }
    }
}