I took a slightly different tack than Chris on embedding Python into Script.  I created an attached property, with the idea that I could set a piece of script "on" an element, giving it some scope.  For example, I got this to work:

<Button Name="Button1" Content="Button1" Grid.Column="0" Grid.Row="1"

      Pythalon:PythonScript.Script ="Target.Click += lambda *args:MessageBox.Show('Hello')">

</Button>

But to do real Python programming, I need to be able to set a multi-line script.  Should be easy enough...just use Property Element syntax:

<Button Name="Button1" Content="Button1" Grid.Column="0" Grid.Row="1"

              <Pythalon:PythonScript.Script>

                   def onClick(*args):

                        MessageBox.Show('Hello Again')

                       

                   Target.Click += onClick

              </Pythalon:PythonScript.Script>

          </Button>

However, when I ran this code....I got a Python parsing error.  The Xaml parser had removed the new lines in the code, so Python saw something like:

   def onClick(*args): MessageBox.Show('Hello Again') Target.Click += onClick

 

Chris had warned me about this issue, and I knew the solution.  Add an xml:space="preserve" attribute.

 

Unfortunately, the Xaml parser doesn't handle this.  I got a message warning me that I couldn't set properties on Property Elements.  Oops.  I reported the bug...but now I'm kinda stuck.  Chris's approach works because he derives from Framework element instead of attaching a property.