On Key Down Handler
<Window x:Class="WpfApplication1.Window1" 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"> <StackPanel> <TextBlock Width="300" Height="20"> Type some text into the TextBox and press the Enter key. </TextBlock> <TextBox Width="300" Height="30" Name="textBox1" KeyDown="OnKeyDownHandler"/> <TextBlock Width="300" Height="100" Name="textBlock1"/> </StackPanel> </Window> //File:Window.xaml.vb Imports System Imports System.Windows Imports System.Windows.Controls Imports System.Windows.Input Namespace WpfApplication1 Public Partial Class Window1 Inherits Window Public Sub New() InitializeComponent() End Sub Private Sub OnKeyDownHandler(sender As Object, e As KeyEventArgs) If e.Key = Key.[Return] Then textBlock1.Text = "You Entered: " + textBox1.Text End If End Sub End Class End Namespace