WPF

<telerik:RadTreeView.ItemTemplate>
	<HierarchicalDataTemplate ItemsSource="{Binding ChildNodes}">
		<Border Background="{Binding BackColour}">
		<StackPanel Orientation="Horizontal">
			<Image Source="{Binding ImageSource,Converter={StaticResource ImageFromAssetsConverter}}"
			 Width="16"
				 Height="16" />
		<TextBlock Margin="10,0"
			Text="{Binding NodeLabel}"
			TextWrapping="Wrap"
			VerticalAlignment="Center" />
		<CheckBox IsChecked="{Binding IsChecked,Mode=TwoWay}"
			Content="Default N/A" Margin="15,0,0,0"
			Visibility="{Binding ShowCheckBox,Converter={StaticResource VisibilityConverter}}" />
		</StackPanel>
	</Border>
</HierarchicalDataTemplate>
</telerik:RadTreeView.ItemTemplate>

public class ReflectionExtension : MarkupExtension
{
    ...
}

<ListBox ItemsSource="{local:Reflection {x:Type Grid}, 
       IncludeMethods=true, IncludeFields=true, IncludeEvents=true}" 
         MaxHeight="200" Grid.Row="3" Grid.ColumnSpan="2" />

<ListBox ItemsSource="{local:MagicClass{x:Type Grid}, 
       IncludeMethods=true, IncludeFields=true, IncludeEvents=true}" 
         MaxHeight="200" Grid.Row="3" Grid.ColumnSpan="2" />

<Button Content="{l:Lang Key=20}" \>

	public class Size123Control : Control
{
	static Size123Control()
	{
		DefaultStyleKeyProperty.OverrideMetadata(typeof(Size123Control), new FrameworkPropertyMetadata(typeof(Size123Control)));
	}
}

public class Size123Panel : Panel
{
    public static int GetSize123(DependencyObject obj) { return (int)obj.GetValue(Size123Property); }

    public static void SetSize123(DependencyObject obj, int value) { obj.SetValue(Size123Property, value); }

	public static readonly DependencyProperty Size123Property = DependencyProperty.RegisterAttached(
		"Size123", typeof(int), typeof(Size123Panel), 
		new FrameworkPropertyMetadata(3,
			FrameworkPropertyMetadataOptions.Inherits
			| FrameworkPropertyMetadataOptions.AffectsMeasure
			| FrameworkPropertyMetadataOptions.AffectsParentMeasure
			| FrameworkPropertyMetadataOptions.AffectsArrange
			| FrameworkPropertyMetadataOptions.AffectsParentArrange
			));

    protected override Size ArrangeOverride(Size finalSize)
    {
        double hTot = 0, h = 0, x = 0, xMax = 0;
        foreach (UIElement child in Children)
        {
            var cs = child.DesiredSize;
            if (x > 0 && x + cs.Width > finalSize.Width)
            {
                hTot += h;
                x = 0;
                h = cs.Height;
            }
            else
            {
                if (cs.Height > h)
                    h = cs.Height;
            }
            child.Arrange(new Rect(new Point(x, hTot), cs));
            x += cs.Width;
            if (x > xMax)
                xMax = x;
        }
        return new Size(xMax, hTot + h);
    }

    protected override Size MeasureOverride(Size availableSize)
    {
        Func<Size> measure = () =>
        {
            double hTot = 0, h = 0, x = 0, xMax = 0;
            foreach (UIElement child in Children)
            {
                child.Measure(availableSize);
                var cs = child.DesiredSize;

                if (x > 0 && x + cs.Width > availableSize.Width)
                {
                    hTot += h;
                    x = 0;
                    h = cs.Height;
                }
                else
                {
                    if (cs.Height > h)
                        h = cs.Height;
                }
                x += cs.Width;
                if (x > xMax)
                    xMax = x;
            }
            return new Size(xMax, hTot + h);
        };

        SetSize123(this, 3);
        var s1 = measure();
        if (s1.Width <= availableSize.Width && s1.Height <= availableSize.Height)
            return s1;

        SetSize123(this, 2);
        var s2 = measure();
        if (s2.Width <= availableSize.Width && s2.Height <= availableSize.Height)
            return s2;

        SetSize123(this, 1);
        var s3 = measure();

        Console.WriteLine("Size123: {0}, {1}, {2}", s1, s2, s3);
        return s3;
    }
}

<Style TargetType="{x:Type local:Size123Control}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:Size123Control}">
                <Border x:Name="MAIN" Width="48" Height="48" Background="Red" BorderThickness="1" BorderBrush="LightGray"/>
                <ControlTemplate.Triggers>
                    <Trigger Property="local:Size123Panel.Size123" Value="2">
                        <Setter TargetName="MAIN" Property="Background" Value="Green"/>
                        <Setter TargetName="MAIN" Property="Width" Value="32"/>
                        <Setter TargetName="MAIN" Property="Height" Value="32"/>
                    </Trigger>
                    <Trigger Property="local:Size123Panel.Size123" Value="1">
                        <Setter TargetName="MAIN" Property="Background" Value="Blue"/>
                        <Setter TargetName="MAIN" Property="Width" Value="16"/>
                        <Setter TargetName="MAIN" Property="Height" Value="16"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<local:Size123Panel>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
    <local:Size123Control/>
</local:Size123Panel>

<GeometryModel3D.Geometry>
                                            <MeshGeometry3D
                                            Positions = "-1,-1,1 1,-1,1 1,1,1 -1,1,1"
                                            TriangleIndices = "0 1 2     2,3,0"
                                            TextureCoordinates="0,1 1,1 1,0 0,0"
                                        />
                                        </GeometryModel3D.Geometry>