I get more questions about this feature than any other from users who are building industrial-strength applications.
Hierarchical data binding allows easy display of nested content.
For example, you want to show a list of customers, but under each customer you want to show all their open orders. With the advent of XML Data, more and more information is deeply nested and requires hierarchy to display the content properly. The inner table is where the real change is. This nesting can be repeated for any number of levels. In the next example , we'll see how three-level nesting is achieved.