WPF C# Tutorial

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="KeyDown Sample" Height="400" Width="500">
  
    
      Type some text into the TextBox and press the Enter key.
    
                 KeyDown="OnKeyDownHandler"/>
    
  


//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }
        private void OnKeyDownHandler(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Return)
            {
                textBlock1.Text = "You Entered: " + textBox1.Text;
            }
        }
    }
}