twin column select

Vaadin 6 / 7 / 8 Framework UI
1

i want to ensure that the user select all the varaibles in the twin column select,how do i do that? Second,how do i get the list of the choosen item ?

2

First…

            Object[] choceList = .....make your list
	preselected = new HashSet<String>();

	... make your preselected list .....

	TwinColSelect tcselect = new TwinColSelect("Select My choices");
	tcselect.setRows(choceList length);
	tcselect.setMultiSelect(true);
	tcselect.setImmediate(true);
	
	for(int i = 0; i < choceList .length; i ++)
	{
		tcselect.addItem((String)choceList [i]

);
}
tcselect.setValue(preselected);

Second…

	Set<String> list = (Set<String>)tcselect.getValue();