Is there a way to chain multiple value converters in XAML?

Question

I've got a situation in which I need to show an integer value, bound to a property on my data context, after putting it through two separate conversions:

1. Reverse the value within a range (e.g. range is 1 to 100; value in datacontext is 90; user sees value of 10)
2. convert the number to a string

I realise I could do both steps by creating my own converter (that implements IValueConverter). However, I've already got a separate value converter that does just the first step, and the second step is covered by Int32Converter.

Is there a way I can chain these two existing classes in XAML without having to create a further class that aggregates them?

If I need to clarify any of this, please let me know. :)

Thanks.

Answer 1

I used this method by Gareth Evans in my Silverlight project.

Here's my implementation of it:

public class ValueConverterGroup : List<IValueConverter>, IValueConverter {     #region IValueConverter Members      public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)     {         return this.Aggregate(value, (current, converter) => converter.Convert(current, targetType, parameter, culture));     }      public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)     {         throw new NotImplementedException();     }      #endregion } 

Which can then be used in XAML like this:

<c:ValueConverterGroup x:Key="InvertAndVisibilitate">    <c:BooleanInverterConverter/>    <c:BooleanToVisibilityConverter/> </c:ValueConverterGroup> 

Answer 2

Found exactly what I was looking for, courtesy of Josh Smith: Piping Value Converters (archive.org link).

He defines a ValueConverterGroup class, whose use in XAML is exactly as I was hoping for. Here's an example:

<!-- Converts the Status attribute text to a SolidColorBrush used to draw       the output of statusDisplayNameGroup. --> <local:ValueConverterGroup x:Key="statusForegroundGroup">   <local:IntegerStringToProcessingStateConverter  />   <local:ProcessingStateToColorConverter />   <local:ColorToSolidColorBrushConverter /> </local:ValueConverterGroup>  

Great stuff. Thanks, Josh. :)