WPF: How to programmatically remove focus from a TextBox

Question

I want to add a simple (at least I thought it was) behaviour to my WPF TextBox.

When the user presses Escape I want the TextBox he is editi

Answer 1

The code I have been using :

// Move to a parent that can take focus
FrameworkElement parent = (FrameworkElement)textBox.Parent;
while (parent != null && parent is IInputElement && !((IInputElement)parent).Focusable)
{
    parent = (FrameworkElement)parent.Parent;
}

DependencyObject scope = FocusManager.GetFocusScope(textBox);
FocusManager.SetFocusedElement(scope, parent as IInputElement);

Answer 2

in .NET Framework 4 just Keyboard.ClearFocus();

Answer 3

My answer does not adress the above question directly, however, I feel that the wording of it has caused it to become "The Question" about programmatically getting rid of focus. A common scenario where this is needed is for the user to be able to clear focus upon left-clicking the background of a root control, like window.

So, to achieve this, you can create an Attached Behavior that will switch focus to a dynamically created control (in my case, an empty label). It is preferrable to use this behavior on the highest-level elements like windows, as it iterates through it's children to find a panel it can add a dummy label to.

public class LoseFocusOnLeftClick : Behavior<FrameworkElement>
{
    private readonly MouseBinding _leftClick;
    private readonly Label _emptyControl = new Label() { Focusable = true, HorizontalAlignment = HorizontalAlignment.Left, VerticalAlignment = VerticalAlignment.Top };

    public LoseFocusOnLeftClick()
    {
        _leftClick = new MouseBinding(new RelayCommand(LoseFocus), new MouseGesture(MouseAction.LeftClick));
    }

    protected override void OnAttached()
    {
        AssociatedObject.InputBindings.Add(_leftClick);
        AssociatedObject.Loaded += AssociatedObject_Loaded;
    }        

    protected override void OnDetaching()
    {
        AssociatedObject.InputBindings.Remove(_leftClick);
        AssociatedObject.Loaded -= AssociatedObject_Loaded;
    }

    private void AssociatedObject_Loaded(object sender, RoutedEventArgs e)
    {
        AssociatedObject.Loaded -= AssociatedObject_Loaded;

        AttachEmptyControl();
    }

    private void AttachEmptyControl()
    {            
        DependencyObject currentElement = AssociatedObject;
        while (!(currentElement is Panel))
        {
            currentElement = VisualTreeHelper.GetChild(currentElement, 0);
        }

        ((Panel)currentElement).Children.Add(_emptyControl);
    }

    private void LoseFocus()
    {            
        _emptyControl.Focus();
    }
}