flex datagrid 自动排序

假设ArrayCollection(m_myArrayCollection)属性有userID,userName,regTime。   
  
1、按regTime排序   
 程序代码   
var m_myArrayCollection:ArrayCollection = new ArrayCollection();   
//先加入N个测试object   
m_myArrayCollection.addItem({userID:0,userName:AAA,regTime:2008-02-28},{userID:1,userName:BBB,regTime:2008-02-29},{userID:2,userName:CCC,regTime:2008-03-01});   
//设定Sort对象   
var m_sort:Sort = new Sort();   
//默认按升序排序   
m_Sort.fields = [new SortField("regTime")];   
//按降序排序，把上一句注释，比对一下效果   
//m_Sort.fields = [new SortField("regTime",true,true)];   
//把排序方法指定给m_myArrayCollection   
m_myArrayCollection.sort = m_sort;   
//如果不执行refresh，啥事都不发生   
m_myArrayCollection.refresh();   
2、先按userID降序排序，再按userName升序排序   
 程序代码   
var m_myArrayCollection:ArrayCollection = new ArrayCollection();   
//先加入N个测试object   
m_myArrayCollection.addItem({userID:0,userName:AAA,regTime:2008-02-28},{userID:1,userName:BBB,regTime:2008-02-29},{userID:2,userName:CCC,regTime:2008-03-01});   
//设定Sort对象   
var m_sort:Sort = new Sort();   
//默认按升序排序   
m_Sort.fields = [new SortField("userID",true,true),new SortField("userName")];   
//把排序方法指定给m_myArrayCollection   
m_myArrayCollection.sort = m_sort;   
//如果不执行refresh，啥事都不发生   
m_myArrayCollection.refresh();