Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/10/29/passing-parameters-to-an-httpservice/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.events.ValidationResultEvent;
            import mx.utils.StringUtil;

            private function submit_click(evt:MouseEvent):void {
                var result:ValidationResultEvent = stringValidator.validate();
                var params:Object = {};

                lbl.text = "";

                switch (result.type) {
                    case ValidationResultEvent.INVALID:
                        Alert.show(result.message, result.type);
                        break;
                    case ValidationResultEvent.VALID:
                        params["name"] = StringUtil.trim(firstName.text);
                        httpServ.send(params);
                        break;
                }
            }
        ]]>
    </mx:Script>

    <mx:StringValidator id="stringValidator"
            source="{firstName}"
            property="text"
            minLength="2"
            maxLength="{firstName.maxChars}" />

    <mx:HTTPService id="httpServ">
        <mx:resultFormat>flashvars</mx:resultFormat>
        <mx:url>http://www.flash-mx.com/mm/greeting.cfm</mx:url>
        <mx:result>lbl.text = httpServ.lastResult.welcomeMessage;</mx:result>
        <mx:fault>Alert.show(event.toString(), event.type);</mx:fault>
    </mx:HTTPService>

    <mx:ApplicationControlBar dock="true">
        <mx:Form>
            <mx:FormItem label="Name:" required="true"
                    direction="horizontal">
                <mx:TextInput id="firstName"
                    maxChars="20" />
                <mx:Button label="Submit"
                        click="submit_click(event);" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:Label id="lbl" fontSize="32" />

</mx:Application>

View source is enabled in the following example.

By popular request, here is the ColdFusion source code as well.

http://www.flash-mx.com/mm/greeting.cfm

<cfsilent>
<cfsetting enablecfoutputonly="Yes">
<cfif IsDefined("URL.name")><cfset Form.Name = URL.name /></cfif>
<cfif NOT IsDefined("Form.name") OR Len(Trim(Form.Name)) EQ 0>
    <cfset Form.Name = "[Mysterious Stranger]" />
</cfif>
</cfsilent><cfcontent reset="true" /><cfoutput>welcomeMessage=#UrlEncodedFormat("Welcome, "&Form.name)#</cfoutput>
<cfsetting enablecfoutputonly="No">

 

Full code after the jump.

View MXML

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2007/09/19/converting-xml-to-objects-using-the-flex-httpservice-mxml-tag/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white"
        creationComplete="serv.send();">

    <mx:Script>
        <![CDATA[
            import mx.rpc.events.FaultEvent;
            import mx.rpc.events.ResultEvent;

            private function serv_result(evt:ResultEvent):void {
                var resultObj:Object = evt.result;
                /* Assign the values... */
                nameText.text = resultObj.album.name;
                img0Text.text = resultObj.album.images.image[0];
                img1Text.text = resultObj.album.images.image[1];
                img2Text.text = resultObj.album.images.image[2];
            }

            private function serv_fault(evt:FaultEvent):void {
                /* Show the error label. */
                error.text += evt.fault.faultString;
                error.visible = true;
                /* Hide the form. */
                form.visible = false;
            }
        ]]>
    </mx:Script>

    <mx:String id="XML_URL">album.xml</mx:String>

    <mx:HTTPService id="serv"
            url="{XML_URL}"
            resultFormat="object"
            result="serv_result(event);"
            fault="serv_fault(event);" />

    <mx:ApplicationControlBar dock="true">
        <mx:Label text="{XML_URL}" />
    </mx:ApplicationControlBar>

    <mx:Label id="error"
            color="red"
            fontSize="36"
            fontWeight="bold"
            visible="false"
            includeInLayout="{error.visible}"/>

    <mx:Form id="form"
            includeInLayout="{form.visible}">
        <mx:FormItem label="resultObj.album.name:">
            <mx:Label id="nameText" />
        </mx:FormItem>
        <mx:FormItem label="resultObj.album.images.image[0]:">
            <mx:Label id="img0Text" />
        </mx:FormItem>
        <mx:FormItem label="resultObj.album.images.image[1]:">
            <mx:Label id="img1Text" />
        </mx:FormItem>
        <mx:FormItem label="resultObj.album.images.image[2]:">
            <mx:Label id="img2Text" />
        </mx:FormItem>
    </mx:Form>

</mx:Application>

View album.xml

<?xml version="1.0" encoding="utf-8"?>
<album>
    <name>One</name>
    <images>
        <image>image1.jpg</image>
        <image>image2.jpg</image>
        <image>image3.jpg</image>
    </images>
</album>

View source is enabled in the following example.

 

Full code after the jump

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="horizontal" verticalAlign="middle" backgroundColor="white" creationComplete="httpParams.send()">

    <mx:HTTPService resultFormat="flashvars" url="{VARIABLES_URL}" id="httpParams" result="onResult(event)" />

    <mx:Script>
        <![CDATA[
            import mx.rpc.events.ResultEvent;
            import mx.collections.ArrayCollection;

            [Bindable]
            private var VARIABLES_URL:String = "http://www.flash-mx.com/mm/params.txt";

            [Bindable]
            private var paramColl:ArrayCollection = new ArrayCollection();

            private function onResult(evt:ResultEvent):void {
                var vars:Object = evt.result;
                var key:String;

                for (key in vars) {
                    paramColl.addItem({key:key, value:vars[key]});
                }
                params.visible = true;
            }
        ]]>
    </mx:Script>

    <mx:VBox>
        <mx:Label text="Parameters:" />
        <mx:DataGrid id="params" dataProvider="{paramColl}" rowCount="5" visible="false">
            <mx:columns>
                <mx:DataGridColumn dataField="key" headerText="Key" />
                <mx:DataGridColumn dataField="value" headerText="Value" />
            </mx:columns>
        </mx:DataGrid>
    </mx:VBox>

</mx:Application>

Again, I’m sure there is a nicer way of handling the ResultEvent and converting to a data provider, so you may want to play around with it a bit.

Of course, if you know the names of the parameters in the file that you’re loading, you could also just do something like this:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" verticalAlign="middle" backgroundColor="white" creationComplete="httpService.send()">

    <mx:HTTPService id="httpService" resultFormat="flashvars" url="params.txt" />

    <mx:VBox>
        <mx:Label text="name: {httpService.lastResult.name}" />
        <mx:Label text="product: {httpService.lastResult.product}" />
        <mx:Label text="powermove: {httpService.lastResult.powermove}" />
        <mx:Label text="skill: {httpService.lastResult.skill}" />
    </mx:VBox>

</mx:Application>

Oh, and remember, since the params.txt file is being loaded at run-time and embedded during compile-time, the params.txt file needs to be relative to the SWF file and not the MXML file.