flex的combBox添加tree

<?xml version="1.0" encoding="utf-8"?> <root> <league label="American League"> <division label="West"> <team label="Los Angeles" /> <team label="Seattle" /> <team label="Oakland" /> <team label="Texas" /> </division> <division label="Central"> <team label="Cleveland" /> <team label="Detroit" /> <team label="Minnesota" /> <team label="Chicago" /> <team label="Kansas City" /> </division> <division label="East"> <team label="Boston" /> <team label="New York" /> <team label="Toronto" /> <team label="Baltimore" /> <team label="Tampa Bay" /> </division> </league> </root>