Given the following XAML:

<Window x:Class="AdornerTesting.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="500" Width="500"
        Loaded="Window_Loaded">
    <Grid Name="grid">
        <Canvas Name="canvas" Width="400" Height="400" Background="LightGoldenrodYellow">
            <RichTextBox Name="richTextBox" Canvas.Top="10" Canvas.Left="10" BorderBrush="Black" BorderThickness="2"
                     Width="200"
                     Height="200"
                     MaxWidth="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Canvas}},Path=ActualWidth}"
                     MaxHeight="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Canvas}},Path=ActualHeight}"/>
        </Canvas>
    </Grid>
</Window>

and a set of adorners being added to the RichTextBox in the Loaded event like so:

AdornerLayer adornerLayer = AdornerLayer.GetAdornerLayer(richTextBox);
adornerLayer.Add(new ResizeAdorner(richTextBox));

How do I keep from being able to resize the RichTextBox beyond the visble bounds of the Canvas?

The ResizeAdorner is essentially the same code that can be found in the MSDN adorner example and it works just fine. Should I be doing something with the bindings of MaxWidth and MaxHeight in the code-behind to calculate how the RichTextBox can be resized? Or is there a way to do this in XAML?