Question

Is there anyway to extract the underlying xaml from a control.

IE. I have a textbox named fooBox. Can I get xaml back from the textbox at runtime that represents the textbox?

Answer 1

This shows you the full lifecycle (from control to XAML back to control).
As you can see,

string s = XamlWriter.Save(value);

is the interesting part you might care about.

    /// <summary>
    /// Clones a given UIElement.  Please note that any events, animations, etc
    /// on the source item may not carry over to the cloned object.
    /// </summary>
    /// <param name="value">UIElement to clone.</param>
    /// <returns>A shallow clone of the source element.</returns>
    public static UIElement CloneUIElement(UIElement value)
    {
        if (value == null)
        {
            return null;
        }

        string s = XamlWriter.Save(value);
        StringReader stringReader = new StringReader(s);
        XmlReader xmlReader = XmlTextReader.Create(stringReader, new XmlReaderSettings());
        return (UIElement)XamlReader.Load(xmlReader);
    }