WPF: Is there a way to use a ValueConverter without defining a resource?

Question

Is there a way to use a ValueConverter without defining it in a resource? As is the syntax is pretty verbose.

Answer 1

You could create an attach property to hook up to the binding and perform the conversion, though if the only reason is for breverity, I wouldn't recommend adding an extra piece of complexity to your code.

Answer 2

Within your converter you can have a static property or field that you can refer to in xaml. No need for adding a resource.

 public class MyConverter : IValueConverter
{
    public static readonly MyConverter Instance = new MyConverter();
... }

And in XAML

<TextBlock Text="{Binding Path=., Converter={x:Static l:MyConverter.Instance}}" />

Beaware that these converters should not store any state as the same instance will be used. If you are iffy about public fields just create a static property instead.

Though it is debatable that this is better

Answer 3

How exactly are you declaring these converters such that verbosity is an issue?

<conv:NegatingConverter x:Key="NegatingConverter" />

One line per converter per application.

Usage isn't verbose either.

Converter="{StaticResource NegatingConverter}"

Answer 4

You can use a MarkupExtension to minimise the amount of xaml code required. E.g:

public class  MyConverter: MarkupExtension, IValueConverter

{ private static MyConverter _converter;

public object Convert(object  value, Type targetType, 
object  parameter, System.Globalization.CultureInfo culture)
{
    // convert and return something
}

public object  ConvertBack(object value, Type  targetType, 
object parameter,  System.Globalization.CultureInfo culture)
{
    // convert and return something (if needed)
}

public override object  ProvideValue(IServiceProvider serviceProvider)
{
    if (_converter == null)
        _converter = new MyConverter();
    return _converter;
}

}

You end up with a syntax like this:

{Binding Converter={conv:MyConverter}}

This approach has an added advantage of ensuring that all your converters are singletons.

This article does a great job of explaining the concept and provides sample code.