<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="" Height="300" Width="300"> <Button Click="ButtonClickedHandler " Name="MyButton" Width="50 " Content="Click Me! " /> <x:Code> void ButtonClickedHandler(object sender, RoutedEventArgs eventArgs) { MyButton.Width = 100 ; MyButton.Content = "Thank you! "; } </x:Code> </Window>