StringValidator

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" verticalAlign="top"

    horizontalAlign="center" backgroundGradientColors="[#570A0A, #731F1F]" paddingTop="0" backgroundGradientAlphas="[1.0, 1.0]">

   

    <mx:Script>

        import mx.controls.Alert;

    </mx:Script>

    <mx:StringValidator source="{fname}" property="text"

        tooShortError="This string is shorter than the minimum allowed length of 4. "

        tooLongError="This string is longer than the maximum allowed length of 20."

        minLength="4" maxLength="20"

        trigger="{myButton}" triggerEvent="click"

        valid="Alert.show('Validation Succeeded!');"/>

       

    <mx:Panel title="StringValidator Example" layout="vertical" color="0xffffff" borderAlpha="0.15"

         paddingTop="10" paddingRight="10" paddingBottom="10" paddingLeft="10" horizontalAlign="center"  x="10" y="10">

        

         <mx:Form color="0x323232">              

            <mx:FormItem label="Enter a name between 4 and 20 characters: ">

                <mx:TextInput id="fname" width="100%"/>

            </mx:FormItem>

            <mx:FormItem >

                <mx:Button id="myButton" label="Validate" />

            </mx:FormItem>

        </mx:Form>

           

    </mx:Panel>

</mx:Application>