Gentlepersons，

Gentlepersons,

一个人如何从MXML中的Flex /动作脚本初始化一个集合实例？

How does one initialize a collection instance from MXML in Flex/Actionscript?

背景

让我们假设：

我已经得到了数名三个列表 对。 在每个列表中的内容从来没有 变化，但我可能要添加新的 在今后的列表中。 用户可以选择列表 使用。 I've got three lists of number-name pairs. The contents of each list never changes, but I may want to add new lists in future. The user can choose which list to use.

我知道如何    用MXML定义/初始化    柔性UI组件，但是这是    我的XML的经验充分的程度。

I know how to use MXML to define/initialize a Flex UI component, but that is the full extent of my XML experience.

问题

我怎样写的XML声明和ActionScript类，这样我可以从XML初始化每个我的三个名单？组合

How do I write a combination of XML declarations and Actionscript classes such that I can initialize each of my three lists from XML?

请注意，我的不可以试图填充一个Flex UI元素（如DataGrid）与各数名对。我只是想读取数据到一个普通的老香草集合。 （一旦我有我的集合初始化的，我可以填充在我的闲暇DataGrid中或什么的。）我无法找到如何解决这个超级简单的情况下，任何文件。文档的一切假设我试图做一些事情要复杂得多，比如访问远程数据库，从而极大地混淆了问题。

Please note that I am not trying to populate a Flex UI element (such as a DataGrid) with the various number-name pairs. I'm just trying to read the data into a plain old vanilla collection. (Once I've got my collections initialized, I can populate DataGrids or whatever at my leisure.) I can't find any documentation of how to address this super-simple case. The documentation all assumes that I'm trying to do something much more complicated, such as accessing a remote database, which confuses the issue tremendously.

谢谢！ ： - ）

吉姆普拉蒙登，得克萨斯州

Jim Plamondon, Texas

推荐答案

有几个方法可以做到这一点：

There's a few ways you can do this:

样本数据集：

<?xml version="1.0" encoding="UTF-8"?>
<events type="array">
    <event>
        <date>12-50-99</date>
        <title>Event A</title>
        <location>San Diego, CA</location>
    </event>
    <event>
        <date>12-50-99</date>
        <title>Event B</title>
        <location>Healdsburg, CA</location>
    </event>
</events>

的Flex 4

XML声明

下面是3种方式来获得数据转换成XML或一个ArrayCollection，这两者可以传递给你的数据提供者。

Flex 4

XML Declarations

Below are 3 ways to get data into XML or an ArrayCollection, both of which you can pass to your data provider.

<?xml version="1.0" encoding="utf-8"?>
<s:Application 
    xmlns:fx="http://ns.adobe.com/mxml/2009"
    xmlns:s="library://ns.adobe.com/flex/spark"
    xmlns:mx="library://ns.adobe.com/flex/mx">

    <fx:Declarations>
        <fx:XML id="data" source="events.xml"/>

        <fx:XML id="data2">
            <event>
                <date>12-50-99</date>
                <title>Event A</title>
                <location>San Diego, CA</location>
            </event>
            <event>
                <date>12-50-99</date>
                <title>Event B</title>
                <location>Healdsburg, CA</location>
            </event>
        </fx:XML>

        <fx:Declarations>
            <mx:ArrayCollection id="data3">
                <fx:Object date="12-50-99" title="Event A" location="San Diego, CA"/>
                <fx:Object date="12-50-99" title="Event B" location="Healdsburg, CA"/>
            </mx:ArrayCollection>
        </fx:Declarations>
    </fx:Declarations>

    <!-- then your views -->
    <mx:Button/>
</s:Application>

Flex 3的工作原理是相同的，但你只是删除＆LT; FX：声明/＆GT; 标签

如果你希望数据是动态的，我只是想创建一个属性为您的ArrayCollection或的XMLListCollection在＆LT; MX：脚本/＆GT; 在你看来块，说 [可绑定]公共变种的myData：ArrayCollection的; ，并通过XML数据装载到这一点。通过保持你的数据外（而不是硬编码/数据嵌入到MXML），你不必重新编译，而且它更容易添加越来越多。

If you want the data to be dynamic, I would just create a property for your ArrayCollection or XMLListCollection in the <mx:Script/> block in your view, say [Bindable] public var myData:ArrayCollection;, and load the data into that via XML. By keeping your data external (not hardcoding/embedding data into MXML), you don't have to recompile, and it's easier to add more and more.

为了做到这一点，你要么需要使用的URLRequest或的HTTPService。的HTTPService基本上是围绕的URLRequest的MXML包装。

In order to do that, you'd either need to use URLRequest or HTTPService. HTTPService is basically an MXML wrapper around the URLRequest.

事情是这样的伪code：

Something like this pseudo code:

<?xml version="1.0" encoding="utf-8"?>
<s:Application 
    xmlns:fx="http://ns.adobe.com/mxml/2009"
    xmlns:s="library://ns.adobe.com/flex/spark"
    xmlns:mx="library://ns.adobe.com/flex/mx"
    initialize="loadData()">
    <fx:Script>

        import mx.collections.*;

        [Bindable] public var list1:IList;
        [Bindable] public var list2:IList;
        [Bindable] public var list3:IList;

        public function loadData():void
        {
            eventsService.load(); // loads, may take a few frames/seconds
        }

        public function updateData(result:Object, property:String):void
        {
            // this["list1"] = xml;
            this[property] = new XMLListCollection(result);
        }

    </fx:Script>

    <fx:Declarations>
        <mx:HTTPService id="eventsService"
            url="events.xml" 
            resultFormat="e4x"
            result="updateData(event.result, 'list1');"
            fault="trace('eventsService Error');"/>
    </fx:Declarations>

    <!-- then your views -->
    <mx:List dataProvider="{list1}"/>
</s:Application>

让我知道，如果工程。