Programmatically setting a silverlight multi-select list box

Is it possible to programatically set the values of a silverlight list box when the selection mode is "multiple"? The "SelectedItems" property is not settable, and "SelectedIndex" only works when the selection mode is "single开发者_Python百科".

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Add items to SelectedItems collection:

myListBox.SelectedItems.Clear();
foreach(var item in selection)
    myListBox.SelectedItems.Add(item);