General guidelines for validation -- Flex 2.01

You should be aware of some guidelines when performing validation on forms. Typically, you associate forms with data models. That lets you trigger validation as part of binding an input user interface control to a field of the data model. You can also perform some of the following actions:

The following example uses many of these guidelines to validate a form made up of several TextInput controls:

<?xml version="1.0"?>
<!-- validators\FullApp.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> 

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

            private var vResult:ValidationResultEvent;

            // Function to validate data and submit it to the server. 
            private function validateAndSubmit():void           {
                // Validate the required fields. 
                vResult = fNameV.validate();
                if (vResult.type==ValidationResultEvent.INVALID) 
                    return;
        
                vResult = lNameV.validate();
                if (vResult.type==ValidationResultEvent.INVALID) 
                    return;

                // Since the date requires 3 fields, perform the validation 
                // when the Submit button is clicked. 
                vResult = dayV.validate();
                if (vResult.type==ValidationResultEvent.INVALID) 
                    return;
    
                // Invoke any other validators or validation logic to make
                // an additional check before submitting the data.

                // Submit data to server.
            }
        ]]>
    </mx:Script>

    <!-- Define the data model. -->
    <mx:Model id="formInfo">
        <formData>
            <date>
                <month>{monthInput.text}</month>
                <day>{dayInput.text}</day>
                <year>{yearInput.text}</year>
            </date>
            <name>
                <firstName>{fNameInput.text}</firstName>
                <lastName>{lNameInput.text}</lastName>
            </name>
            <phoneNum>{phoneInput.text}</phoneNum>
        </formData>
    </mx:Model>

    <!-- Define the validators. -->
    <mx:StringValidator id="fNameV" 
        required="true"
        source="{fNameInput}" 
        property="text"/>
    <mx:StringValidator id="lNameV" 
        required="true" 
        source="{lNameInput}" 
        property="text"/>
    <mx:PhoneNumberValidator id="pnV"
        source="{phoneInput}" 
        property="text"/>

    <!-- Invoke the DataValidator programmatically. -->
    <mx:DateValidator id="dayV" 
        triggerEvent="" 
        daySource="{dayInput}" dayProperty="text" 
        monthSource="{monthInput}" monthProperty="text" 
        yearSource="{yearInput}" yearProperty="text"/>

    <!-- Define the form to populate the model. -->
    <mx:Form>
        <mx:FormItem label="Month">
            <mx:TextInput id="monthInput"/>
        </mx:FormItem>
        <mx:FormItem label="Day">
            <mx:TextInput id="dayInput"/>
        </mx:FormItem>
        <mx:FormItem label="Year">
            <mx:TextInput id="yearInput"/>
        </mx:FormItem>
        <mx:FormItem label="First name">
            <mx:TextInput id="fNameInput"/>
        </mx:FormItem>
        <mx:FormItem label="Last name">
            <mx:TextInput id="lNameInput"/>
        </mx:FormItem>
        <mx:FormItem label="Phone">
            <mx:TextInput id="phoneInput"/>
        </mx:FormItem>
    </mx:Form>

    <!-- Define the button to trigger validation. -->
    <mx:Button label="Submit"
        click="validateAndSubmit();"/>
</mx:Application>