From your usercontrol, you can get the visual parent, which is the canvas you put it in. To get the visual parent, use:
| VisualTreeHelper.GetParent(this); |
VisualTreeHelper is a helper class that allows you to walk the visual tree. The visual tree is a tree built up of UI elements, ordered in the way that they are currently visible (rendered). You also have the logicalTree, which represents the tree structure of your xaml (this can be different from the visual tree).