This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
What do you mean by completely filled with data - when the data is loaded, or the component is rendered? DataGrid has a dataChange event that will fire when the data is set on the DataGrid. Waiting for a CreationComplete event should be OK if you need to wait till after the lifecycle of the comonent has run and it is visible on the stage.