WPF

namespace Abtech.Spares.UI.Classes
{
    [ValueConversion(typeof(bool), typeof(Visibility))] 
    public sealed class BoolToVisibilityConverter : IValueConverter 
    {   
        public Visibility TrueValue { get; set; }   
        public Visibility FalseValue { get; set; }    

        public BoolToVisibilityConverter()   
        {     
            TrueValue = Visibility.Visible;     
            FalseValue = Visibility.Collapsed;   
        }    

        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)   
        {     
            if (!(value is bool))       
                return null;     
        
            return (bool)value ? TrueValue : FalseValue;       
        }    

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)   
        {     
            if (Equals(value, TrueValue))       
                return true;     
            
            if (Equals(value, FalseValue))       
                return false;     
            
            return null;   
        } 
    } 
}

<UserControl x:Class="Abtech.Spares.UI.Views.ChildContentView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:Abtech.Spares.UI.Classes;assembly=Abtech.Spares.UI"
             xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
             mc:Ignorable="d" 
             d:DesignHeight="300" 
             d:DesignWidth="300">

    <UserControl.Resources>
        <local:BoolToVisibilityConverter          
            x:Key="BoolToHiddenConverter"          
            TrueValue="Visible" 
            FalseValue="Hidden" />
    </UserControl.Resources>

    <Grid>

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Abtech.Spares.UI	The tag 'BoolToVisibilityConverter' does not exist in XML namespace 'clr-namespace:Abtech.Spares.UI.Classes;assembly=Abtech.Spares.UI'. Line 13 Position 10.

public partial class Property
{
    private string _displayAddress;
    public string DisplayAddress
    {
        get
        {
            string address = number.ToString();
            if (!String.IsNullOrEmpty(direction))
                address += " " + direction;
            address += " " + street;
            if (suffixId != null)
                address += " " + StreetSuffix.name;
            if (!String.IsNullOrEmpty(unit))
                address += " " + unit;
            return address;
        }
        set { _displayAddress = value; }
    }
}

[Include]
public StreetSuffix StreetSuffix { get; set; }