In this tutorial Shawn Oster shows how to add connecting lines using Blend 3.
One of the more annoying things when trying a do a little research into how you can tweak a control is having to come up with some kind of mock data to work with, especially when working with a TreeView because of its hierarchical nature. Blend 3 introduced a huge time-saving feature, Sample Data, that we’ll take advantage of.
For this example I want to end up with a common TreeView UI pattern, an icon followed by some text, similar to a basic file browser. With those requirements in mind lets create some sample data.