Вам необходимо указать свои CommandBindings и Button следующим образом:
<Window.CommandBindings>
<CommandBinding Command="ApplicationCommands.Close"
Executed="CloseCommandHandler"
CanExecute="CanExecuteHandler"
/>
</Window.CommandBindings>
....
<Button Margin="3" Command="ApplicationCommands.Close" Content="Ok" Width="50"/>
И затем настроить обработчики Executed и CanExecute:
private void CloseCommandHandler(object sender, ExecutedRoutedEventArgs e)
{
//Do something
}
private void CanExecuteHandler(object sender, CanExecuteRoutedEventArgs e)
{
//Determine whether handler can execute
e.CanExecute = true;
}
Надеюсь, это поможет.