about Flex DataGrid edit

Summary(¸ÅÊö)£º Adobe Flex µÄ dataGrid ÓкÜÇ¿´óµÄ¹¦ÄÜ£¬±ÈÈçItemRenderer,headerRendererµÈ£¬¿ÉÒÔ·½±ãµØʵÏÖ×Ô¼ºÏëÒªµÄ¹¦ÄÜ¡£µ«¶ÔdataGridÖ±½Ó±à¼­²¢±£´æµ½Service¶Ë£¬¾ÍÓеãÂé·³ÁË¡£
Requirement(ÐèÇó)£º ¶ÔdataGrid½øÐе¥Î»¸ñ±à¼­£¬ÈôÓб仯£¬±£´æµ½Service; ·ñÔò²»±£´æ¡£
Solution(½â¾ö·½°¸): ÔËÓÃDataGrid µÄ itemEditBegin ʼþ¡¢itemFocusOut ʼþ¡£
1.  when the itemEditBegin is dispatched, the event handler should save this cell value as old value.(±à¼­Ç°±£´æ¾ÉÖµ)
2. when the listener of itemFocusOut is responding, you should check the current cell to the old value. If it's value have changed, you should save the new value to Service.(±à¼­ºóÅжϣ¬ÊÇ·ñ¸ü¸Ä¡£)
Example(Àý×Ó)  as follow:
<mx:Script>
        <![CDATA[
private var oldValueOfEditedItem: CreditVO;
   private function creditDGEditBegin(event: DataGridEvent): void {
             oldValueOfEditedItem = (event.itemRenderer.data as CreditVO).clone() as CreditVO;
            }
            private function editedItemChanged(newValue: CreditVO): Boolean {
             return (newValue.amount != oldValueOfEditedItem.amount)|| 
               (newValue.description != oldValueOfEditedItem.description);
            }
            private function creditDGEditEnd(event: DataGridEvent): void {
             var newValue: CreditVO = event.itemRenderer.data as CreditVO;
             if (editedItemChanged(newValue)) {
             dispatchEvent(new UpdateCreditEvent(newValue))
             }
            }
  ]]>
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