The best way to learn how to use the component is to use the Demo to see what options are available and then reference the source code in the examples folder to understand how it’s implemented. It’s also a good idea to skim through the methods and properties in the ASDoc file (as the demo doesn’t use every property/method available). Here are the two files: AutoComplete and AdvancedAutoComplete.

Although the component doesn’t extend from the ComboBox class, it’s designed to have as similar an interface as possible. For example, it implements the filterFunction, labelFunction and selectedItems properties as well as others.

Here’s the simplest possible implementation of the component.

<?xml version="1.0" encoding="utf-8"?>
			import mx.collections.ArrayCollection;
			private var _data:ArrayCollection = new ArrayCollection( ["one", "two", "three"] );
	<components:AutoComplete dataProvider="{ _data }" />

While there are a fair number of settings you can adjust, I’d like to start by the showing the way I generally use the component.

<components:AutoComplete dataProvider="{ _data }" 
	prompt="Please select" backspaceAction="remove" 

I’ve set three properties which I’ll review quickly here.

  • selectedItemStyleName: Controls the look of the selected items. There are four choices: macMail, facebook, underline and none.
  • prompt: A string to display when no value is set.
  • backSpaceAction: Determines what to do when a user clicks backspace. By default we focus the item (ala Mac Mail) but this can be changed to remove it.

Working with the data

Like most other Flex components you can set either the labelField or labelFunction property. By default this will control how the item is displayed through out the component (in the drop down, once selected and in the browsers).

You have a couple of choices for customizing the drop down label. You can define a dropDownLabelFunction which returns an HTML string to handle formatting the item. This is used in the email demo to display the person’s email address (ie, “Homer Simpson “) in the drop down. If you’d like greater control you can set a dropDownItemRenderer. This can be seen in the Color Chooser demo.

If multiple selection is enabled the component can contain both selected items and a search string. Because of this I’ve need to add a searchText property which can be used to get/set the search string. The text property returns a string representation of the selected items.

Related to this there are two main events which the component dispatches: change and searchChange. The change event is dispatched when the selectedItem property changes, while the searchChange event is dispatched when the search string is changed.

To filter the data you can either use the built in options by setting the “matchType” property or create a custom filter by setting a value for the “filterFunction” property. The built in options are:

  • beginning: Only match the beginning of the string.
  • word: Match the beginning of any of the words in the string.
  • anyPart: Matches any part of the string.

All of the built in options perform a case-insensitive search. Here’s how you could use the filterFunction property to implement a case-sensisitve search.

		import com.hillelcoren.utils.StringUtils;
		import mx.collections.ArrayCollection;
		private var _data:ArrayCollection = new ArrayCollection( ["ONE", "TWO", "THREE"] );
		private function filterFunction( item:String, searchStr:String ):Boolean
			return searchStr == item.substr( 0, searchStr.length );
<components:AutoComplete dataProvider="{ _data }" filterFunction="filterFunction"/>

To select items you have three options, you can use either selectedItem, selectedItems or selectedItemId. The first two options are pretty standard so I won’t cover them here. Setting the selectedItemId property will cause the component to search the items in the dataProvider for an object with a matching id. By default, it looks for a field called “id” on the item but you can set a custom field using the keyField property.

Out of the box the component requires the user to select an item from the list. You can allow the user to enter their own values by setting allowNewValues to true. You can then control whether or new the new items are editable by setting the allowEditingNewValues property. Additionally, you can set the allowDuplicates property to control whether or not to allow an item to be selected more than once.

A common question is how to use the component with data returned from the server. The best practice is to use a change listener. Once the user has entered enough characters fire off your data request. Once the data has been returned and passed to the dataProvider you can call the search() method to tell the component to filter the items and display the drop down. You can check out the DynamicData.mxml file in the examples folder to see the details.

You can use either an ArrayCollection or an XMLListCollection as the dataProvider. I showed you an example with an ArrayCollection earlier on, here’s an example using an XMLListCollection.

<mx:XML format="e4x" id="xml">  
<mx:XMLListCollection id="xmlList" source="{ xml.item }"/>   	
<components:AutoComplete dataProvider="{ xmlList }"/>

Usability settings

Multiple Selection

This is the one feature which separates the component from other the AutoCompletes out there, setting the allowMultipleSelection to true enables the user to select more than one value. The AdvancedAutoComplete extends this feature by adding a selectionLayout property which when set to vertical causes the selected items to be displayed in a List component.


The AutoSelect functionality will automatically select an item if it matches a case-insensitive string comparison and is the only match found. This feature can be disabled by setting autoSelectEnabled to false.

If you’d like to use a custom function to determine if an item should be auto-selected you can set a value for the autoSelectFunction property. Here’s an example where we use this property to auto-select once when there is a single match. For example, typing “o” will select “one” right away.

		import mx.collections.ArrayCollection;
		private var _data:ArrayCollection = new ArrayCollection( ["one", "two", "three"] );
		private function selectFunction( item:String, searchStr:String ):Boolean
			return true;
<components:AutoComplete dataProvider="{ _data }" autoSelectFunction="selectFunction" />

Clear Icon

The core of the component is the PromptTextInput class. This class provides two main features: the prompt and the clear icon. We covered the prompt earlier but the clear icon is a little gray x icon which appears if there is text in the component. Note, this feature only works if allowMultipleSelection is set to false.

Drop Down

The number of items displayed in the drop down is controlled by the dropDownRowCount property. By default, the width of the drop down will
be set to match the width of the TextInput. However this can be overriden using the dropDownWidth property. On the topic of the drop down, you can use the showDropDown, hideDropDown and isDropDown visible to show/hide the drop down.


The challenge in building a component with lots of features is keeping it as streamlined as possible. In order to support adding more advanced functionality while not bloating the component I’ve created an AdvancedAutoComplete class which extends the AutoComplete component.

Selection Layout

As discussed earlier, setting the selectionLayout to vertical causes the items to be displayed in a List. When using the vertical layout you can use the showRemoveButton property to control whether or not to show a remove button.


This can be enabled by either setting the showBrowseButton property to true, or by adding an options to the action menu (as is demonstrated in the Color Chooser Demo). By default we show a pop window which contains a searchable DataGrid. You can control which fields of the data to display in the grid using the browserFields property. If multiple selection is enabled, you can set the useListBuilder property to true to display a two column browser instead. If you’d like to implement your own browser you can either extends one the existing ones are create a component which implements the IBrowser interface. You’ll then need to set the browserClass property to your new class.


If the selectionLayout is set to vertical you can enable the user to order the items in the list by setting the showOrderButtons property to true. If using the List Builder the ordering buttons will also be displayed in it.

Actions Menu

To enable the action menu you need to set a value for the actionsMenuDataProvider. This is just a regular Flex Menu component so all the usual features are supported (ie, using checkboxes). Here’s a link to the supported menu attributes. You can see an example of how to use this feature in the code for the AdvancedDemo. If enabled the menu can be displayed by pressing the down button while the component has focus.

Odds and Ends

Custom Skins

The selected items are simply buttons, this means it’s pretty easy to change the look and feel using skins. The styles which the component comes with (macMail, facebook, etc) are all implement using skins. It’s possible to define your own custom skin. If you’d like to implement it you can check out the CustomSkin.mxml file in the examples folder.

First Class Components

The component is made up of a number of classes. Some of these classes are useful in their own right. I consider the following three classes to be first class components:

  • PromptTextInput: This is a TextInput with two additional features, you can set a prompt which will appear when no value is set and a clear icon will appear when there is a value set and the mouse is over the component.
  • ListBuilder: This is a two column browser which can be used to add/remove items from a list.
  • CloseableTitleWindow: Adds a key listener to the TitleWindow which enables the user to click the ESC key to close it.

Utility Classes

The com/hillelcoren/utils folder contains a couple of helper classes. There are some useful functions here which you may be able to use elsewhere in your applications. Some examples include a function to compare if two ArrayCollections are equal and functions to convert string to/from camel caps.


You can use a regular validator to make sure that a value is selected. Here’s a simple example demonstrating how to implement it.

<mx:Validator source="{ autoComplete }" property="selectedItem"/> 
<components:AutoComplete id="autoComplete" dataProvider="{ _data }"/>

Inline Button

You can use the inlineButton property to set a button to appear at the end of the component. This feature is used in the AdvancedAutoComplete for the button used to display the actions menu. Here’s an example of how you can use this property to display a button which causes the drop down to appear (ala a regular ComboBox)

		import mx.collections.ArrayCollection;

		private var _data:ArrayCollection = new ArrayCollection( ["one","two","three"] );

		private function handleButtonClick():void
			if (autoComplete.isDropDownVisible())


<components:AdvancedAutoComplete id="autoComplete" dataProvider="{ _data }">
		<mx:Button skin="mx.skins.halo.ComboBoxArrowSkin" click="handleButtonClick()"/>

That about does it, hopefully you found this useful. I plan to continue to improve the documentation over time. If anything here is unclear, or if there are other areas you’d like me to cover please post a comment and I’ll update the page.


544 thoughts on “Documentation”

  1. Hilllel,

    For the custom skin, when I specify the name of the style using ‘selectedItemStyleName’, compiler complains that ‘selectedItemStyleName’ may only have one of 4 predefined values (macMail, facebook, underline, none). How do you then recommend specifying custom skin.


  2. In this autocomplete. i had a drop down display position problem.
    when i enter into autocomplete box the “dropDownItemRenderer” is dispalying somewhere upper side . there is a gap between autocomplete and ItemRenderer. please find out the issue

    1. I’m sorry, I’m no longer actively supporting the component. If you want to dig into the code I’d suggest starting with the positionDropDown function (I think that’s what it was called).

  3. I have a problem with autocomplete its taking 10-15 seconds to load approximately 5343 records into the component after getting the data from service call.Could you please suggest me to speed this up.

  4. Hi Hillel,

    We are trying to build a auto component and your AutoComplete with facebook style exactly suites our requirement. But our security team has told not to use any thrid party URL like xmlns:components=”com.hillelcoren.components.*” in the mxml files. In that case I would to copy your .as file and make a copy of it locally so that I can use the control locally.
    I am not able to find .as source code under download section. can you please help me with this?

  5. isModeEditable is very nice to make it read only, but I still can click it and press ‘delete’ on keyboard to delete this, or down on keyboard to select new object from the list when inactive. Any solution to this?

  6. Hello Hillel, pretty awesome component! I have a question… for me skins doesn’t work at all… it display a normal s:Button as selectedItems… any advice or something that I forgot to get? PD: Flash builder 4.5

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