Question

只是想知道是否有人知道子类ComboBox的现有组件，但是允许你在列表中指定一个标题为“all”或“none”的项目，将selectedItem设置为null？我已经考虑过编写一个，并且由于组件的内部结构看起来很多工作，所以我想知道是否有人已经完成了它？

Answer 1

当没有选择项目时，ComboBox会是什么样子？或者为此选择的所有项目？听起来你应该使用List代替ComboBox。查看Tour de Flex上的列表控件。

Answer 2

this.

之类的内容

Answer 3

运行：

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" width="100%" height="100%" creationComplete="onCreationComplete()">
    <mx:Script>
        <![CDATA[
            private var myData:Array = new Array();

            [Bindable]
            private var comboData:Array = new Array();

            [Bindable]
            private var selectedData:String = "";

            private function onCreationComplete():void
            {
                myData.push({"label" : "First", "value" : "First"});
                myData.push({"label" : "Second", "value" : "Second"});
                myData.push({"label" : "Third", "value" : "Third"});

                comboData.push({"label" : "<None>", "value" : "<None>"});
                comboData.push({"label" : "<All>", "value" : "<All>"});
                for(var i:int = 0; i < myData.length; i++) {
                    comboData.push(myData[i]);
                }
            }

            private function onSmartComboBoxChange():void
            {
                if(smartComboBox.selectedItem) {
                    if(smartComboBox.selectedItem.value == "<None>") {
                        selectedData = "";
                    } else if(smartComboBox.selectedItem.value == "<All>") {
                        selectedData = "";
                        for(var i:int = 0; i < myData.length; i++) {
                            selectedData += myData[i].value + ", ";
                        }
                    } else {
                        selectedData = comboData[smartComboBox.selectedIndex].value;
                    }
                }
            }
        ]]>
    </mx:Script>
    <mx:VBox>
        <mx:ComboBox id="smartComboBox" dataProvider="{comboData}" change="onSmartComboBoxChange()" labelField="label" />
        <mx:Label id="selectedDataLabel" text="{selectedData}" />
    </mx:VBox>
</mx:Application>

Flex ComboBox子类带有“Null”/“All”选项？

3 个答案: