设置Flex combobox控件提示功能-优快云博客

本文介绍如何使用 Flex ComboBox 控件并设置其提示信息。通过设置 prompt 属性和使用 ActionScript (AS) 实现提示功能的动态控制。示例中展示了如何在用户未选择任何项时显示默认提示。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

以下的例子将展示如何通过设置prompt属性来设置Flex ComboBox控件的提示功能。

DE<你可以通过设置selectedIndex值为-1来使得ComboBox的重新显示提示信息！DE<

'; } else { whichEl.style.display = 'none'; sb.innerHTML=' 显示代码'; whichEl.witdh="300px"; } } 隐藏代码

当然你可以用AS来实现上述的功能

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


<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...";
                addChild(comboBox);
            }

            private function button_click(evt:MouseEvent):void {
                comboBox.selectedIndex = -1;
            }
        ]]>
    </mx:Script>

</mx:Application>
DE<