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出可以對XML元素與對象指派外,你也可以通過使用E4X組裝與傳遞XML對象。
下邊的例子中,你可以使用prependChild()和appendChild()方法來向XML對象的清單中的前邊或後邊增減一個屬性。類似 的,使用insertChildBefore()方法和insertchildAfter()方法來增加屬性在指定的屬性之前或之後。要删除元素,使用 delete()方法從XML中移除節點。
<?xml version="1.0" encoding="utf-8"?>
<mx:Application
xmlns:mx="http://www.adobe.com/2006/mxml"
width="500" height="600"
creationComplete="myDataGrid.selectedIndex=0; validateForm();"
>
<mx:Script>
<!--[CDATA[
import mx.controls.Alert;
// Constants
private const SELECTED_ITEM:uint = 0;
private const THE_LIST:uint = 1;
private const BEFORE:uint = 0;
private const AFTER:uint = 1;
// Flag: is the form valid?
[Bindable]
private var formIsValid:Boolean;
// Flag: does a selection exist in the data grid?
[Bindable]
private var selectionExists:Boolean;
// Holds the index of the next item in the
// data grid following the deletion of a book item.
private var newSelectedIndex:int;
// Model: XML structure describing
// some of the books in my collection.
[Bindable]
private var myBooks:XML =
<books>
<book ISBN="1590595181">
<title>Foundation ActionScript Animation: Making Things Move</title>
<author>Keith Peters</author>
<amazonUrl>http://tinyurl.com/npuxt</amazonUrl>
</book>
<book ISBN="1582346194">
<title>Send in the Idiots: Stories from the Other Side of Autism</title>
<author>Kamran Nazeer</author>
<amazonUrl>http://tinyurl.com/lo5ts</amazonUrl>
</book>
</books>
// Add a new book.
private function addBookHandler():void
{
// Create a new XML Object from the form information
var newBook:XML =
<book ISBN={isbnInput.text}>
<title>{titleInput.text}</title>
<author>{authorInput.text}</author>
<amazonUrl>{amazonUrlInput.text}</amazonUrl>
</book>;
// Save the selected book's index so it can be reselected
// in the grid once the new book is added.
var selectedBookIndex:uint = myDataGrid.selectedIndex;
// Does the user want to add the new
// book relative to the selected book in the
// data grid or relative to the list itself?
if (addRelativeTo.selectedIndex == SELECTED_ITEM)
{
// Add the new item relative to the selected item.
var selectedBook:XML = myBooks.book[selectedBookIndex];
// Does the user want to add it before or after
// the selected item?
if (addPosition.selectedIndex == BEFORE)
{
// Add new item before selected item
myBooks = myBooks.insertChildBefore(selectedBook, newBook);
}
else
{
// Add new item after selected item
myBooks = myBooks.insertChildAfter(selectedBook, newBook);
}
}
else
{
// Add the new item relative to the whole list of books.
if (addPosition.selectedIndex == BEFORE)
{
// Add new item at the start of the list.
myBooks = myBooks.prependChild(newBook);
}
else
{
// Add new item at the end of the list.
myBooks = myBooks.appendChild(newBook);
}
}
// Select the previously selected item in the grid
// so the user doesn't lose their position. (If a new book was
// added before the currently selected item, that item's
// new index will be one greater, so select that.)
var newSelectedIndex:uint = (addPosition.selectedIndex == BEFORE) ? selectedBookIndex + 1: selectedBookIndex;
myDataGrid.selectedIndex = newSelectedIndex;
}
// Delete selected book
private function deleteBookHandler():void
{
// Save the currently selected index.
var selectedBookIndex:int = myDataGrid.selectedIndex;
// Delete the currently selected book.
delete (myBooks.book[selectedBookIndex]);
// Reselect the next logical item in the data grid.
newSelectedIndex = (selectedBookIndex==0) ? 0 : selectedBookIndex - 1;
// Change the selected index of the data grid
// at a later frame. See note on changeDataGridIndex()
// method for more details on this workaround.
callLater ( changeDataGridIndex );
}
// This is a workaround for a known issue with
// List-based components where deleting an item
// from the control's dataProvider leaves the
// selectedIndex at an incorrect value. The workaround
// is to reassign the data provider at least a
// frame later and to change the index there.
private function changeDataGridIndex ():void
{
// Reassign the data grid's data provider.
myDataGrid.dataProvider = myBooks.book;
// Set the selected index.
myDataGrid.selectedIndex = newSelectedIndex;
// Validate the form to make sure that there
// is actually a selection (that the grid is
// not empty).
validateForm();
}
// Perform simple form validation.
private function validateForm():void
{
// Is the form valid?
formIsValid =
isbnInput.text != ""
&& titleInput.text != ""
&& authorInput.text != ""
&& amazonUrlInput.text != "";
// Does a selection exist in the data grid?
selectionExists = myDataGrid.selectedIndex != -1;
}
]]-->
</mx:Script>
<!-- User interface -->
<mx:Panel
title="Assigning XML data"
paddingBottom="10" paddingLeft="10" paddingRight="10" paddingTop="10"
>
<!-- List of books -->
<mx:DataGrid
id="myDataGrid"
dataProvider="{myBooks.book}"
change="validateForm();"
>
<mx:columns>
<mx:DataGridColumn dataField="@ISBN" headerText="ISBN" width="85"/>
<mx:DataGridColumn dataField="title" headerText="Title"/>
<mx:DataGridColumn dataField="author" headerText="Author"/>
<mx:DataGridColumn dataField="amazonUrl" headerText="Web site">
<mx:itemRenderer>
<mx:Component>
<mx:LinkButton
label="Visit"
click="navigateToURL(new URLRequest(data.amazonUrl), 'blank');"
/>
</mx:Component>
</mx:itemRenderer>
</mx:DataGridColumn>
</mx:columns>
</mx:DataGrid>
<!-- New book form. Prepopulated with a book for easier testing. -->
<mx:Form width="100%" autoLayout="false">
<mx:FormHeading label="New book details"/>
<mx:FormItem label="ISBN:" width="
100%">
<mx:TextInput
id="isbnInput"
width="100%"
text="1590596196"
change="validateForm();"
/>
</mx:FormItem>
<mx:FormItem label="Title:" width="100%">
<mx:TextInput
id="titleInput"
width="100%"
text="Object Oriented Actionscript for Flash 8"
change="validateForm();"
/>
</mx:FormItem>
<mx:FormItem label="Author:" width="100%">
<mx:TextInput
id="authorInput"
width="100%"
text="Peter Elst"
change="validateForm();"
/>
</mx:FormItem>
<mx:FormItem label="Amazon Url" width="100%">
<mx:TextInput
id="amazonUrlInput"
width="100%"
text="http://tinyurl.com/qxon2"
change="validateForm();"
/>
</mx:FormItem>
</mx:Form>
<mx:TextArea id="deb" width="100%"/>
<mx:ControlBar>
<mx:Button
label="Add book"
click="addBookHandler();"
enabled="{formIsValid}"
/>
<mx:ComboBox id="addPosition" enabled="{formIsValid}">
<mx:String>before</mx:String>
<mx:String>after</mx:String>
</mx:ComboBox>
<mx:ComboBox
id="addRelativeTo"
enabled="{formIsValid}"
>
<mx:String>selected item.</mx:String>
<mx:String>the list.</mx:String>
</mx:ComboBox>
<mx:VRule height="15"/>
<mx:Button
label="Delete book"
click="deleteBookHandler();"
enabled="{selectionExists}"
/>
</mx:ControlBar>
</mx:Panel>
</mx:Application>