C#.NET

namespace SDKSample {
    public class ExampleClass : ContentControl {
        public ExampleClass() {
            ...
        }
    }
}

<Page x:Class="WPFApplication1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:custom="clr-namespace:SDKSample;assembly=SDKSampleLibrary">
  ...
  <custom:ExampleClass/>
...
</Page>

// Adorners must subclass the abstract base class Adorner.
public class SimpleCircleAdorner : Adorner
{
    // Be sure to call the base class constructor.
    public SimpleCircleAdorner(UIElement adornedElement)
    : base(adornedElement)
    {
        ...
    }

    // A common way to implement an adorner's rendering behavior is to override the OnRender
    // method, which is called by the layout system as part of a rendering pass.
    protected override void OnRender(DrawingContext drawingContext)
    {
        Rect adornedElementRect = new Rect(this.AdornedElement.DesiredSize);

        // Some arbitrary drawing implements.
        SolidColorBrush renderBrush = new SolidColorBrush(Colors.Green);
        renderBrush.Opacity = 0.2;
        Pen renderPen = new Pen(new SolidColorBrush(Colors.Navy), 1.5);
        double renderRadius = 5.0;

    // Draw a circle at each corner.
        drawingContext.DrawEllipse(renderBrush, renderPen, adornedElementRect.TopLeft, renderRadius, renderRadius);
        drawingContext.DrawEllipse(renderBrush, renderPen, adornedElementRect.TopRight, renderRadius, renderRadius);
        drawingContext.DrawEllipse(renderBrush, renderPen, adornedElementRect.BottomLeft, renderRadius, renderRadius);
        drawingContext.DrawEllipse(renderBrush, renderPen, adornedElementRect.BottomRight, renderRadius, renderRadius);
    }
}