initialize="dataGrid_creationCompleteHandler(); or whatever
you want to call the method.
At the point of creationComplete your datagrid has already
drawn itself. During the initialize the properties are set for each
column to use before it draws itself.
I have never manipulated grid columns widths programatically
after it has drawn itself so I am not sure how to do this. (I would
think it would be possible). You could also define the width within