(99)999-9999
(__)___-____
public class MaskVisibilityBehavior : Behavior<MaskedTextBox> {
private FrameworkElement _contentPresenter;
protected override void OnAttached() {
base.OnAttached();
AssociatedObject.Loaded += (sender, args) => {
_contentPresenter = AssociatedObject.Template.FindName("PART_ContentHost", AssociatedObject) as FrameworkElement;
if (_contentPresenter == null)
throw new InvalidCastException();
AssociatedObject.TextChanged += OnTextChanged;
AssociatedObject.GotFocus += OnGotFocus;
AssociatedObject.LostFocus += OnLostFocus;
UpdateMaskVisibility();
};
}
protected override void OnDetaching() {
AssociatedObject.TextChanged -= OnTextChanged;
AssociatedObject.GotFocus -= OnGotFocus;
AssociatedObject.LostFocus -= OnLostFocus;
base.OnDetaching();
}
private void OnLostFocus(object sender, RoutedEventArgs routedEventArgs) {
UpdateMaskVisibility();
}
private void OnGotFocus(object sender, RoutedEventArgs routedEventArgs) {
UpdateMaskVisibility();
}
private void OnTextChanged(object sender, TextChangedEventArgs textChangedEventArgs) {
UpdateMaskVisibility();
}
private void UpdateMaskVisibility() {
_contentPresenter.Visibility = AssociatedObject.MaskedTextProvider.AssignedEditPositionCount > 0 ||
AssociatedObject.IsFocused
? Visibility.Visible
: Visibility.Hidden;
}
}
<xctk:MaskedTextBox Mask="(000) 000-0000"
ValueDataType="{x:Type s:String}">
<i:Interaction.Behaviors>
<local:MaskVisibilityBehavior />
</i:Interaction.Behaviors>
</xctk:MaskedTextBox>
