Flex DropDownLis控件

介绍

DropDownList控件包含一个下拉列表，用户可以从中选择与HTML中的SELECT表单元素类似的单个值。

类声明

以下是 spark.components.DropDownList 类的声明:

public class DropDownList 
   extends DropDownListBase 

公共属性

公共方法

继承的方法

此类继承以下类中的方法:

• spark.components.supportClasses.DropDownListBase

• spark.components.List

• spark.components.supportClasses.ListBase

• spark.components.SkinnableDataContainer

• spark.components.supportClasses.SkinnableContainerBase

• spark.components.supportClasses.SkinnableComponent

• mx.core.UIComponent

• mx.core.FlexSprite

• flash.display.Sprite

• flash.display.DisplayObjectContainer

• flash.display.InteractiveObject

• flash.display.DisplayObject

• flash.events.EventDispatcher

• Object
  

Flex DropDownList控件示例

让我们按照以下步骤通过创建测试应用程序来检查Flex应用程序中DropDownList控件的使用:

以下是修改后的mxml文件 src / com.tutorialspoint / HelloWorld.mxml 的内容。

<?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"
   width="100%" height="100%" minWidth="500" minHeight="500"
   >

   <fx:Style source="/com/tutorialspoint/client/Style.css"/>

   <fx:Script>
      <![CDATA[
         import mx.collections.ArrayCollection; 
         import spark.events.IndexChangeEvent;
		 
         [Bindable]
         public var data:ArrayCollection = new ArrayCollection(
         [   
            {value:"France", code:"FR"},
            {value:"Japan", code:"JP"},
            {value:"India", code:"IN"},
            {value:"Russia", code:"RS"},
            {value:"United States", code:"US"}		
         ]                
         );

         protected function dropDownList_changeHandler
           (event:IndexChangeEvent):void
         {
            ddlIndex.text=dropDownList.selectedIndex.toString();
            ddlSelectedItem.text=dropDownList.selectedItem.value;
            ddlCode.text=dropDownList.selectedItem.code;
         }

      ]]>
   </fx:Script>
   <s:BorderContainer width="550" height="400" id="mainContainer"
   styleName="container">
      <s:VGroup width="100%" height="100%" gap="50" horizontalAlign="center"
      verticalAlign="middle">
         <s:Label id="lblHeader" text="Form Controls Demonstration" 
         fontSize="40" color="0x777777" styleName="heading"/>
         <s:Panel id="dropDownListPanel" title="Using DropDownList" 
            width="420" height="200">
            <s:layout>
               <s:VerticalLayout  gap="10" verticalAlign="middle" 
                  horizontalAlign="center"/>	
            </s:layout>
            <s:HGroup>
               <s:Label text="Index :"/>
               <s:Label id="ddlIndex" fontWeight="bold"/>
               <s:Label text="Value :"/> 
               <s:Label id="ddlSelectedItem" 
                  text="{dropDownList.selectedItem.value}" fontWeight="bold"/>
               <s:Label text="Code :"/> 
               <s:Label id="ddlCode" 
                  text="{dropDownList.selectedItem.code}" fontWeight="bold"/>
            </s:HGroup>				
            <s:DropDownList  id="dropDownList" dataProvider="{data}" 
               width="150" change="dropDownList_changeHandler(event)"
               selectedIndex="0" labelField="value"/>     				
         </s:Panel>
      </s:VGroup>	 
   </s:BorderContainer>	
</s:Application>

准备好所有更改后，让我们以正常模式编译和运行应用程序，就像在 Flex - 创建应用程序中一样 章节。 如果一切顺利，您的应用程序，这将产生以下结果:[在线试用]