When 2 grids are linked

When you have:

• a web page
• 2 DataGridViews (parent/child relationship)
• user wants to insert a new record into parent grid
• parent grid has datasource set to Nothing so that EmptyDataTemplate shows
• EmptyDataTemplate contains a DetailView
• user fills in fields and clicks Insert

Then you get:

• the parent record saves correctly; and
• the page refreshes; but 
• an error occurs because the child grid is linked to an empty Parent grid.
• No amount of fiddling with the SelectedItem property of the Parent grid seems to work.

Resolution:

• Hide the second grid until the user manually makes a selection on the Parent grid.