BindingSample / ExpandoBindingWpf

MainWindow.xaml

<Window
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:ExpandoBindingWpf"
        xmlns:Dynamic="clr-namespace:System.Dynamic;assembly=System.Core"
        x:Class="ExpandoBindingWpf.MainWindow"
        Title="Expando Binding" Height="400" Width="600" FontSize="36">
    <Window.DataContext>
        <Dynamic:ExpandoObject/>
    </Window.DataContext>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <TextBox Text="{Binding Input, UpdateSourceTrigger=PropertyChanged}" TextWrapping="Wrap"/>
        <TextBlock Text="{Binding Output}" TextWrapping="Wrap" Grid.Row="1"/>
    </Grid>
</Window>

MainWindow.xaml.cs

using System;
using System.ComponentModel;
using System.Windows;

namespace ExpandoBindingWpf
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            dynamic model = DataContext;

            ((INotifyPropertyChanged)model).PropertyChanged += (o, e) =>
            {
                if (e.PropertyName == "Input")
                    model.Output = model.Input?.ToUpper();
            };
        }
    }
}