Flex 2 Developer's Guide > Building User Interfaces for Flex Applications > Using Data Providers and Collections > Using remote data providers

Using remote data providers

You can use the following types of remote data providers for Flex components:

• RPC data sources: HTTPService components, WebService components, and RemoteObject components
• Flex DataService components that you use in conjunction with the server-side Flex Data Management Service to distribute and synchronize data among multiple client applications.

The following sections describe how you can use these remote data sources to provide data. For more information on using remote data providers see Using RPC Components.

Subtopics

Using an RPC data source

To use an RPC data source, you represent the result of the remote service by using the appropriate class as follows:

• The RemoteObject class automatically returns as an ArrayCollection any data that is represented on the server as a java.util.List object, and you can use the returned object directly.
• Otherwise, including for HTTPService and WebService results, convert the return data to a collection class if the data changes or if you use the same result in multiple places (in the latter case, you increase efficiency). As a general rule, use an ArrayCollection for serialized (list-based) objects or an XMLListCollection for data in E4X format.

The following code excerpt shows this use, converting a list returned by a web service to an ArrayCollection:

    <mx:WebService id="employeeWS" destination"employeeWS"
        showBusyCursor="true"
        fault="alert(event.fault.faultstring)">
        <mx:operation name="getList">
            <mx:request>
                <deptId>{dept.selectedItem.data}</deptId>
            </mx:request>
        </mx:operation>
.
.
    </mx:WebService>

    <mx:ArrayCollection id="ac"
        source="mx.utils.ArrayUtil.toArray(employeeWS.getList.lastResult)"/>
    <mx:DataGrid dataProvider="{ac}" width="100%">

For more information on using RPC data sources, see Using RPC Components.

Using a DataService component

To use a DataService component as a data provider, you call the component's fill() method to fill an ArrayCollection object with the data from a Data Management Service destination, as the following code excerpt shows:

<mx:Script>
    <![CDATA[
        import mx.data.DataService;
        import mx.collections.ArrayCollection;
        
        public var ds:DataService;
        [Bindable]
        public var contacts:ArrayCollection;

        public function initApp()
        {
            contacts = new ArrayCollection();
            ds = new DataService("contact");
            ds.fill(contacts);    
        }
    ]]>
</mx:Script>
.
.
        <mx:DataGrid id="dg" dataProvider="{contacts}" editable="true">

For more information on using DataService components, see Distributing Data in Flex Applications.

Flex 2

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