Binding off Visibility of another element - and inverting

Question

I'd like to make Control A visibile if Control B is hidden, and vice versa. Right now I have this converter:

public class InvertVisibilityConverter : IValueConverter {

    public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture) {
        if (targetType == typeof(Visibility)) {
            Visibility vis = (Visibility)value;
            return vis == Visibility.Collapsed ? Visibility.Visible : Visibility.Collapsed;
        }
        throw new InvalidOperationException("Converter can only convert to value of type Visibility.");
    }

    public Object ConvertBack(Object value, Type targetType, Object parameter, CultureInfo culture) {
        throw new Exception("Invalid call - one way only");
    }
}

And this XAML:

<Button Visibility="{Binding ElementName=btn1, Path=Visibility, Converter={StaticResource InvertVisibilityConverter}}">Btn2</Button>

Which works. I'm just wondering if there's a more direct way in WPF / Silverlight to accomplish this? I don't mind having a converter, I just want to make sure there's no better way I'm not aware of.

Answer 1

In this case you could do it with triggers. Example with two Buttons

<Button Name="button1">
    <Button.Style>
        <Style>
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=button2, Path=Visibility}" Value="Visible">
                    <Setter Property="Button.Visibility" Value="Hidden"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Button.Style>
</Button>
<Button Name="button2"/>

Answer 2

Bottom line, I see no problem with what you are doing.

That said, if you have a property in the ViewModel to which Control A binds to control its visibility, I would bind Control B to the same property and invert the visibily via a separate converter. I'm not sure if I can articulate why, but that seems more natural to me (at least in lieu of any additional context around what you are doing).

Answer 3

What you doing is fine but I tend to prefer more general converters and to keep symmetry with the built in converters.

So I would do a InverseBooleanToVisibiltyConverter that accepts booleans and returns visibility types. This matches with the built in BoolenToVisibiltyConverter

Then I would bind to the IsVisible property of the button not the Visibility property.

But that is a matter of preference really.