maui-linux/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue5003.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:Xamarin.Forms.Controls.Issues"
             x:Class="Xamarin.Forms.Controls.Issues.Issue5003">
    <ContentPage.Resources>
        <ResourceDictionary>
            <local:StrikeThroughIfTrueConverter x:Key="StrikeThroughIfTrueConverter"/>
        </ResourceDictionary>
    </ContentPage.Resources>
    <ContentPage.Content>
    <Label  Text="{Binding MyNullString}" 
                TextDecorations="{Binding SomeBoolean, Converter={StaticResource StrikeThroughIfTrueConverter}}"/>
    </ContentPage.Content>
</ContentPage>