GWT - Samples

event dispatching and handling has become much easier with Handlers. You can invent your own Event types, and use them in the same way as all the other Handlers.

When the value of any TextBox changes I want to do something with the value but i need to know the row number of the changed TextBox

You maybe want the Grid to rather extend Composite and fire the onValueChange() events, that way you only need one ChangeHandler listening on all the TextBox’s (rather than one Handler per TextBox).