[flexcoders] get selected datagrid dynamically

[Jason B]

Im trying to get the selected item value from the parent app but i
cannot seem to put the name as a variable?

var fieldname:String = columnData.field;

        create_text = new TextInput();
                         create_text.percentWidth = 80;
                         create_text.id = "inputtext" + counter;

//***THIS LINE IS THE ISSUE
create_test.text =
parentApplication.reftables_grid.selecteditem.[fieldname];

I can alert the fieldname fine showing the data grid's field name but
i need to use it as a variable to get the selected items value from
the grid