Ans:

ArrayCollection:

The ArrayCollection class is a wrapper class that exposes an Array as a collection that can be accessed and manipulated using the methods and properties of the ICollectionView or IList interfaces. Operations on a ArrayCollection instance modify the data source; for example, if you use the removeItemAt() method on an ArrayCollection, you remove the item from the underlying Array.

For example:

<?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" 
               minWidth="955" minHeight="600">
    <s:layout>
        <s:VerticalLayout/>
    </s:layout>
    <fx:Script>
        <![CDATA[
            private function gridinitialize():void {
                data.dataProvider = [
                    {aName:'Bikrant', DOB:'01/01/1986', 
                        City:'Delhi', State:'NewDelhi'},
                    {aName:'Brijesh', DOB:'15/07/1984', 
                        City:'Noida', State:'Uttar Pradesh'},
                    {aName:'Gaurav', DOB:'27/06/1989', 
                        City:'Mumbai', State:'Maharashtra'}                 
                ];
            }
        ]]>
    </fx:Script>
    <s:Panel title="DataGrid Control Example" width="428" height="409">
        <mx:DataGrid id="data" 
                     initialize="gridinitialize()" 
                     x="12" y="12" 
                     borderColor="#000000" 
                     borderStyle="solid" 
                     chromeColor="#000000" 
                     color="#90BB2A" 
                     fontFamily="verdana" 
                     fontGridFitType="pixel" 
                     symbolColor="#FFFFFF" 
                     textAlign="center"/>

    </s:Panel>  
</s:Application>

ListCollectionView:

The ListCollectionView class adds the properties and methods of the ICollectionView interface to an object that conforms to the IList interface. As a result, you can pass an object of this class to anything that requires an IList or ICollectionView.

This class also lets you use [ ] array notation to access the getItemAt() and setItemAt() methods. If you use code such as myListCollectionView[index] Flex calls the myListCollectionView object's getItemAt() or setItemAt() method.

For example:

<?xml version="1.0"?>
<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" 
               minWidth="955" minHeight="600">
    <s:Panel title="List dataProvider test" creationComplete="onCreate()"
        paddingTop="10" paddingBottom="10" paddingLeft="10" paddingRight="10">

        <mx:List id="list" width="100%" dataProvider="{filtered_stuff}"/>
        <s:Button click="addItem()" label="Add item"/>
    </s:Panel>

    <fx:Script>
<![CDATA[
import mx.collections.ListCollectionView;
import mx.collections.ArrayCollection;

[Bindable] public var stuff:ArrayCollection;
[Bindable] public var filtered_stuff:ListCollectionView;

public function addItem():void {
    trace("adding item", stuff.length);
    stuff.addItem({label: stuff.length});
}

public function onCreate():void {
    stuff = new ArrayCollection([{label: 0}]);
    filtered_stuff = new ListCollectionView(stuff);
    filtered_stuff.filterFunction = function(item:Object):Boolean {
        return item.label > 0;
    }
    filtered_stuff.refresh();
}
]]>
    </fx:Script>
</s:Application>