The list based controls in Flex has the built in support for the drag and drop.So to support the drag and drop operations for the non-list based components(here TextInput) we must handle the drag and drop events.
Go through the classes involded in the drag and drop operations,drag and drop events for a drag initiator,drag and drop events for a drop target to explicitly handle the drag and drop and to fully understand the drag and drop operations functionality.
For now enjoy the below demo and code.

October 6, 2009 at 9:09 pm |
Thank you very much for your post on Drag and Drop:List Control to TextInput. I have adapted the drop handler to build buttons on a panel from an array, and am continuing to play. I am a novice to Flex and your generosity is much appreciated.
Rick
November 5, 2009 at 4:03 am |
Hi,
your welcome and thank you., i am just sharing my knowledge,and i am glad it helped you.
regards,
kumar.