ItemPage.xaml

<?xml version="1.0" encoding="UTF-8" ?>
<rxui:ReactiveContentPage
    x:Class="ReactiveToDoSample.Views.ItemPage"
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:rxui="clr-namespace:ReactiveUI.XamForms;assembly=ReactiveUI.XamForms"
    xmlns:vm="clr-namespace:ReactiveToDoSample.ViewModels"
    x:TypeArguments="vm:ItemViewModel">
    <rxui:ReactiveContentPage.ToolbarItems>
        <ToolbarItem Command="{Binding CloseCommand}" Text="Close" />
    </rxui:ReactiveContentPage.ToolbarItems>
    <StackLayout>
        <Label Text="Item"
               FontSize="Title"
               Padding="20"
               HorizontalOptions="Center"/>
        <Frame Style="{StaticResource CardFrameStyle}"
               Margin="10"
               VerticalOptions="Start">
            <StackLayout
                HorizontalOptions="FillAndExpand">
                <Entry Placeholder="Title"
                       Text="{Binding Title}" />
                <Button Command="{Binding SaveCommand}"
                        Style="{StaticResource MainButtonStyle}"
                        Text="Save"/>
            </StackLayout>
        </Frame>
   </StackLayout>
</rxui:ReactiveContentPage>