<fx:XML> tag implemented by the compiler

---

The <fx:XML> tag is a compile-time tag that generates an XML object or XMLNode object from a text model. The tag has the following features that are not provided directly by the Flash classes:

• You can specify a file as the source of the XML text model.
• You can use MXML binding expressions in the XML text to extract node contents from variable data; for example, you could bind a node's name attribute to a text input value, as in the following line:
     <child name="{textInput1.text}"/>
  
• You can use the format="xml" attribute to generate a legacy XMLNode object instead of an E4X-format XML object.

MXML Syntax

You can place an <fx:XML> tag in a Flex application file or in an MXML component file. The <fx:XML> tag must have an id attribute value to be referenced by another component. The <fx:XML> tag does not need an id attribute value if the tag is a direct child of an <mx:dataProvider> tag. The tag body must have a single root node containing all child nodes. The <fx:XML> tag cannot be the root tag of an MXML component. You cannot specify Flash XML or XMLNode class properties in the tag; you must specify these in ActionScript.

The <fx:XML> tag has the following syntax:

    <fx:XML
       id="modelID"
       format="e4x|xml">
          <root>
             child nodes
          </root>
    </fx:XML> 

or:

    <fx:XML
       id="modelID"
       format="e4x|xml"
       source="fileName"
       />

The default format property value of e4x creates an XML object, which implements the XML-handling standards defined in the ECMA-357 specification (known as "E4X"). For backward compatibility, you can set the format property to xml to generate an object of the type flash.xml.XMLNode.

The source property specifies an external source, such as a file, for the data model. The external source can contain static data and data binding expressions. The compiler reads the source value and compiles the source into the application; the source value is not read at runtime.

The following example uses the tag to define a model for a MenuBar control:

    <?xml version="1.0"?>
    <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:mx="library://ns.adobe.com/flex/halo" 
        xmlns:s="library://ns.adobe.com/flex/spark"
        backgroundColor="#FFFFFF">
    
        <fx:XML format="e4x" id="myMenuModel">
            <root label="Menu">
            <menuitem label="MenuItem A">
                <menuitem label="SubMenuItem 1-A"/>
                <menuitem label="SubMenuItem 2-A" />
            </menuitem>
            <menuitem label="MenuItem B"/>
            <menuitem label="MenuItem C" type="check"/>
            <menuitem type="separator"/>
            <menuitem label="MenuItem D">
                <menuitem label="SubMenuItem 1-D" type="radio" groupName="one"/>
                <menuitem label="SubMenuItem 2-D" type="radio" groupName="one"/>
                <menuitem label="SubMenuItem 3-D" type="radio" groupName="one"/>
            </menuitem>
            </root>
        </fx:XML>
    
    
        <mx:MenuBar id="myMenu" labelField="@label" showRoot="true">
            <mx:dataProvider>
                {myMenuModel}
            </mx:dataProvider>
        </mx:MenuBar>
    
    </s:Application>

---

© 2009 Adobe Systems Incorporated. All rights reserved.
Sat Oct 3 2009, 04:30 AM -07:00