This demo shows how to manually update/insert items to the database. The new values
are extracted from the current item using the ExtractValues method.
Note that, when inserting a child item to a parent data item, the foreign key values (the ReportsTo
field in our case, specified by the ParentDataKeyNames array in RadTreeList) are
extracted into the Hashtable with ExtractValues. We need to check if the foreign
key is present in the Hashtable and add it to the insert parameters. When inserting
a root item, however, foreign keys are not populated and thus, DbNull should be
explicitly added as a foregn key.