Setting the dropdown menu border color on a ComboBox control in Flex

The following example shows how you can set the border color for a Flex ComboBox control’s dropdown menu by setting the dropdownBorderColor style.

Full code after the jump.

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/21/setting-the-dropdown-menu-border-color-on-a-combobox-control-in-flex/ -->
<mx:Application name="ComboBox_dropdownBorderColor_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="top"
        backgroundColor="white">

    <mx:Array id="arr">
        <mx:Object label="One" />
        <mx:Object label="Two" />
        <mx:Object label="Three" />
        <mx:Object label="Four" />
        <mx:Object label="Five" />
        <mx:Object label="Six" />
        <mx:Object label="Seven" />
        <mx:Object label="Eight" />
        <mx:Object label="Nine" />
        <mx:Object label="Ten" />
    </mx:Array>

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="dropdownBorderColor:">
                <mx:ColorPicker id="colorPicker" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:ComboBox id="comboBox"
            dataProvider="{arr}"
            dropdownBorderColor="{colorPicker.selectedColor}" />

</mx:Application>

You can also set the dropdownBorderColor style in an external .CSS file or <mx:Style /> block, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/21/setting-the-dropdown-menu-border-color-on-a-combobox-control-in-flex/ -->
<mx:Application name="ComboBox_dropdownBorderColor_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="top"
        backgroundColor="white">

    <mx:Style>
        ComboBox {
            dropdownBorderColor: red;
        }
    </mx:Style>

    <mx:Array id="arr">
        <mx:Object label="One" />
        <mx:Object label="Two" />
        <mx:Object label="Three" />
        <mx:Object label="Four" />
        <mx:Object label="Five" />
        <mx:Object label="Six" />
        <mx:Object label="Seven" />
        <mx:Object label="Eight" />
        <mx:Object label="Nine" />
        <mx:Object label="Ten" />
    </mx:Array>

    <mx:ComboBox id="comboBox"
            dataProvider="{arr}" />

</mx:Application>

You can also set the dropdownBorderColor style using ActionScript, as seen in the following example:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/21/setting-the-dropdown-menu-border-color-on-a-combobox-control-in-flex/ -->
<mx:Application name="ComboBox_dropdownBorderColor_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="top"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.events.ColorPickerEvent;

            private function colorPicker_change(evt:ColorPickerEvent):void {
                comboBox.setStyle("dropdownBorderColor", evt.color);
            }
        ]]>
    </mx:Script>

    <mx:Array id="arr">
        <mx:Object label="One" />
        <mx:Object label="Two" />
        <mx:Object label="Three" />
        <mx:Object label="Four" />
        <mx:Object label="Five" />
        <mx:Object label="Six" />
        <mx:Object label="Seven" />
        <mx:Object label="Eight" />
        <mx:Object label="Nine" />
        <mx:Object label="Ten" />
    </mx:Array>

    <mx:ApplicationControlBar dock="true">
        <mx:Form styleName="plain">
            <mx:FormItem label="dropdownBorderColor:">
                <mx:ColorPicker id="colorPicker"
                        change="colorPicker_change(event);" />
            </mx:FormItem>
        </mx:Form>
    </mx:ApplicationControlBar>

    <mx:ComboBox id="comboBox"
            dataProvider="{arr}" />

</mx:Application>

Due to popular demand, here is the “same” example in a more ActionScript friendly format:

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/09/21/setting-the-dropdown-menu-border-color-on-a-combobox-control-in-flex/ -->
<mx:Application name="ComboBox_dropdownBorderColor_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="top"
        backgroundColor="white"
        initialize="init();">

    <mx:Script>
        <![CDATA[
            import mx.containers.ApplicationControlBar;
            import mx.containers.Form;
            import mx.containers.FormItem;
            import mx.controls.ColorPicker;
            import mx.controls.ComboBox;
            import mx.events.ColorPickerEvent;

            private var arr:Array;
            private var colorPicker:ColorPicker;
            private var comboBox:ComboBox;

            private function init():void {
                arr = [];
                arr.push({label:"One"});
                arr.push({label:"Two"});
                arr.push({label:"Three"});
                arr.push({label:"Four"});
                arr.push({label:"Five"});
                arr.push({label:"Six"});
                arr.push({label:"Seven"});
                arr.push({label:"Eight"});
                arr.push({label:"Nine"});
                arr.push({label:"Ten"});

                colorPicker = new ColorPicker();
                colorPicker.addEventListener(ColorPickerEvent.CHANGE, colorPicker_change);

                var formItem:FormItem = new FormItem();
                formItem.label = "dropdownBorderColor:";
                formItem.addChild(colorPicker);

                var form:Form = new Form();
                form.styleName = "plain";
                form.addChild(formItem);

                var appControlBar:ApplicationControlBar;
                appControlBar = new ApplicationControlBar();
                appControlBar.dock = true;
                appControlBar.addChild(form);
                addChildAt(appControlBar, 0);

                comboBox = new ComboBox();
                comboBox.dataProvider = arr;
                addChild(comboBox);
            }

            private function colorPicker_change(evt:ColorPickerEvent):void {
                comboBox.setStyle("dropdownBorderColor", evt.color);
            }
        ]]>
    </mx:Script>

</mx:Application>