Question

I want to use WPF DataTrigger to check value greater than X. I know that this is only possible with IValueConverter. I have found many C# examples for that, but I need it in powershell. Could someone help me translate this to powershell?

The C# code to translate:

public class CutoffConverter : IValueConverter {
    public object ConvertTo(object obj, Type type) {
        return ((int)obj) > Cutoff;
    }

    public object ConvertFrom(object obj, Type type) {
        throw new NotImplementedException();
    }

    public int Cutoff { get; set; }
}

And the XAML

<Window.Resources>
    <myNamespace:CutoffConverter x:Key="AgeConverter"/>
</Window.Resources>

<DataTemplate.Triggers>
    <DataTrigger Binding="{Binding Path=Age,
                           Converter={StaticResource AgeConverter},
                           ConverterParameter=30}">
        <Setter TargetName="Age" Property="Foreground" Value="Red"/> 
    </DataTrigger>
</DataTemplate.Triggers>

Answer 1

Sure:

$src = @'
using System;
using System.Globalization;
using System.Windows.Data;

namespace MyNamespace
{
    public class CutoffConverter : IValueConverter
    {
        public int Cutoff { get; set; }

        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return ((int)value) > Cutoff;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}
'@

Add-Type -AssemblyName PresentationFramework    
Add-Type -TypeDefinition $src -ReferencedAssemblies PresentationFramework

You can add most any C# code this way. And you pretty much need to use C# because AFAIK you can’t implement interfaces in PowerShell script. It is more of a CLI consumer language and not so much a producer language.