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The library allows to createIValueConverter,IMultiValueConverter,DataTemplateSelector, andValidationRule objects with the most convenient syntax available, ideally, using the lambda expressions.

First create a (static) class and define your converters as static fields (or properties):

internalstaticclassConverters{publicstaticreadonlyIValueConverterVisibleIfTrue=ValueConverter.Create<bool,Visibility>(e=>e.Value?Visibility.Visible:Visibility.Collapsed);publicstaticreadonlyIValueConverterVisibleIfNotNull=ValueConverter.Create<object,Visibility>(e=>e.Value!=null?Visibility.Visible:Visibility.Collapsed);publicstaticreadonlyIValueConverterToUpperCase=ValueConverter.Create<string,string>(e=>e.Value.ToUpper());}

You're done! Just reference the converters with thex:Static expressions from your XAML files (assuming thatc is the namespace definition for theConverters class):

<ButtonVisibility="{Binding model.IsAvailable, Converter={x:Static c:Converters.VisibleIfTrue}}" /><TextBlockText="{Binding model.Heading, Converter={x:Static c:Converters.ToUpperCase}}" />

• strongly-typed converters
• resource declaration not needed, just use thex:Static expressions
• separate class for each converter not needed anymore
• no redundant declarations: if you do not need theConvertBack method, don't define it; otherwise, just put the second lambda expression
• full support for the remaining parameters of theConvert andConvertBack methods: theculture and theparameter (also strongly-typed) are accessible as well
• if the conversion fails due to unexpected value types the optionalerror strategy can be specified

The library also allows to createDataTemplateSelector objects in the same convenient way as value converters. In order to define a selector simply write a static field (or property) similar to this snippet:

internalstaticclassTemplateSelector{publicstaticDataTemplateSelectorAlternatingText=LambdaConverters.TemplateSelector.Create<int>(            e=>e.Item%2==0?(DataTemplate)((FrameworkElement)e.Container)?.FindResource("BlackWhite"):(DataTemplate)((FrameworkElement)e.Container)?.FindResource("WhiteBlack"));}

Use your Lambda DataTemplateSelectors by referencing it with thex:Static markup extention (assuming thats is the namespace definition for theTemplateSelector class):

<UserControl.Resources>    <DataTemplatex:Key="BlackWhite">        <TextBlockText="{Binding}"Foreground="Black"Background="White" />    </DataTemplate>    <DataTemplatex:Key="WhiteBlack">        <TextBlockText="{Binding}"Foreground="White"Background="Black" />    </DataTemplate></UserControl.Resources><DockPanel>    <ListBoxItemsSource="{Binding IntNumbers}"ItemTemplateSelector="{x:Static s:TemplateSelector.AlternatingText}">    </ListBox></DockPanel>

Tada! All even numbers fromIntNumbers are displayed with black font and white background and the odd numbers get the inverse font and background colors.

• strongly-typed Selectors
• resource declaration not needed, just use thex:Static expressions
• separate class for each selector not needed anymore
• full support for the remaining parametercontainer. For example, if you need to grab aDataTemplate from where the selector is use (see the example above).

Furthermore, you'll get Lambda ValidationRules on top. By now you know "the drill". First, define aValidationRuleobject like this:

publicstaticclassRule{publicstaticValidationRuleIsNumericString=LambdaConverters.Validator.Create<string>(            e=>e.Value.All(char.IsDigit)?ValidationResult.ValidResult:newValidationResult(false,"Text has non-digit characters!"));}

And then reference your new rule in vourView (assuming thatr is the namespace definition for theRule class):

<TextBox>    <TextBox.Text>        <BindingPath="Text"UpdateSourceTrigger="PropertyChanged">            <Binding.ValidationRules>                <x:StaticMember="r:Rule.IsNumericString"/>            </Binding.ValidationRules>        </Binding>    </TextBox.Text></TextBox>

Now, you made sure that only strings which consists of digits are passed to yourViewModel.

• strongly-typed rules
• resource declaration not needed, just use thex:Static expressions
• separate class for each rule not needed anymore
• full support for the remaining parameterculture

Use the NuGet package manager to install the package.

💡ReSharper users: use the Extension Manager to install the external annotations for the library.

The library currently supports the WPF only.

Please feel free toreport them.