ComboBox控件的prompt属性.

示例:


代码:

<?xml version="1.0" encoding="utf-8"?>

<!-- http://blog.flexexamples.com/2008/06/01/setting-a-prompt-on-a-combobox-control-in-flex/ -->

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

        layout="vertical"

        verticalAlign="top"

        backgroundColor="white">


    <mx:Array id="arr">

        <mx:Object abbrev="AL" name="Alabama" />

        <mx:Object abbrev="AK" name="Alaska" />

        <mx:Object abbrev="AZ" name="Arizona" />

        <mx:Object abbrev="AR" name="Arkansas" />

        <mx:Object abbrev="CA" name="California" />

        <mx:Object abbrev="CO" name="Colorado" />

        <mx:Object abbrev="CT" name="Connecticut" />

    </mx:Array>


    <mx:ApplicationControlBar dock="true">

        <mx:Button id="button"

                label="Reset ComboBox"

                click="comboBox.selectedIndex = -1;" />

    </mx:ApplicationControlBar>


    <mx:ComboBox id="comboBox"

            dataProvider="{arr}"

            labelField="name"

            prompt="Please select a state设置ComboBox控件的提示内容._ide" />


</mx:Application>



通过as来实现:

<?xml version="1.0" encoding="utf-8"?>

<!-- http://blog.flexexamples.com/2008/06/01/setting-a-prompt-on-a-combobox-control-in-flex/ -->

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"

        layout="vertical"

        verticalAlign="top"

        backgroundColor="white"

        initialize="init();">


    <mx:Script>

        <![CDATA[

            import mx.controls.ComboBox;

            import mx.controls.Button;

            import mx.containers.ApplicationControlBar;


            private var arr:Array;

            private var appControlBar:ApplicationControlBar;

            private var button:Button;

            private var comboBox:ComboBox;


            private function init():void {

                arr = [];

                arr.push({abbrev:"AL", name:"Alabama"});

                arr.push({abbrev:"AK", name:"Alaska"});

                arr.push({abbrev:"AZ", name:"Arizona"});

                arr.push({abbrev:"AR", name:"Arkansas"});

                arr.push({abbrev:"CA", name:"California"});

                arr.push({abbrev:"CO", name:"Colorado"});

                arr.push({abbrev:"CT", name:"Connecticut"});


                button = new Button();

                button.label = "Reset ComboBox";

                button.addEventListener(MouseEvent.CLICK, button_click);


                appControlBar = new ApplicationControlBar();

                appControlBar.dock = true;

                appControlBar.addChild(button);

                Application.application.addChildAt(appControlBar, 0);


                comboBox = new ComboBox();

                comboBox.dataProvider = arr;

                comboBox.labelField = "name";

                comboBox.prompt = "Please select a state设置ComboBox控件的提示内容._ide";

                addChild(comboBox);

            }


            private function button_click(evt:MouseEvent):void {

                comboBox.selectedIndex = -1;

            }

        ]]>

    </mx:Script>


</mx:Application>