See the FillNestedGridsGrid method in the Virtual Nested Grids sample - this is FlyGrid initilization method, and inspect event handlers that connected to FlyGrid.Net in this method to know how node data and chidren of parent node is fetched.
All you should do to convert this sample to your needs:
1. change columns initilization (you can use Preparecolumns from databoundGridForm.cs for these purposes)
2. change event handlers code to fetch data from dataview instead of data arrays used in this code as sources of data.