Adobe® Flex® 4 Language Reference
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mx.validators 
StringValidator 
Packagemx.validators
Classpublic class StringValidator
InheritanceStringValidator Inheritance Validator Inheritance EventDispatcher Inheritance Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

The StringValidator class validates that the length of a String is within a specified range.

MXML SyntaxexpandedHide MXML Syntax

The <mx:StringValidator> tag inherits all of the tag attributes of its superclass, and add the following tag attributes:

  <mx:StringValidator
    maxLength="NaN" 
    minLength="NaN" 
    tooLongError="This string is longer than the maximum allowed length. This must be less than {0} characters long." 
    tooShortError="This string is shorter than the minimum allowed length. This must be at least {0} characters long." 
  />

View the examples


Public Properties
 PropertyDefined By
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
 Inheritedenabled : Boolean
Setting this value to false will stop the validator from performing validation.
Validator
 Inheritedlistener : Object
Specifies the validation listener.
Validator
  maxLength : Object
Maximum length for a valid String.
StringValidator
  minLength : Object
Minimum length for a valid String.
StringValidator
 Inheritedproperty : String
A String specifying the name of the property of the source object that contains the value to validate.
Validator
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
 Inheritedrequired : Boolean = true
If true, specifies that a missing or empty value causes a validation error.
Validator
 InheritedrequiredFieldError : String
Error message when a value is missing and the required property is true.
Validator
 Inheritedsource : Object
Specifies the object containing the property to validate.
Validator
  tooLongError : String
Error message when the String is longer than the maxLength property.
StringValidator
  tooShortError : String
Error message when the string is shorter than the minLength property.
StringValidator
 Inheritedtrigger : IEventDispatcher
Specifies the component generating the event that triggers the validator.
Validator
 InheritedtriggerEvent : String
Specifies the event that triggers the validation.
Validator
Protected Properties
 PropertyDefined By
 InheritedactualListeners : Array
[read-only] Contains an Array of listener objects, if any, or the source object.
Validator
 InheritedactualTrigger : IEventDispatcher
[read-only] Contains the trigger object, if any, or the source object.
Validator
 InheritedresourceManager : IResourceManager
[read-only] A reference to the object which manages all of the application's localized resources.
Validator
 InheritedsubFields : Array
An Array of Strings containing the names for the properties contained in the value Object passed to the validate() method.
Validator
Public Methods
 MethodDefined By
  
StringValidator()
Constructor.
StringValidator
 Inherited
addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void
Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.
EventDispatcher
 Inherited
dispatchEvent(event:Event):Boolean
Dispatches an event into the event flow.
EventDispatcher
 Inherited
hasEventListener(type:String):Boolean
Checks whether the EventDispatcher object has any listeners registered for a specific type of event.
EventDispatcher
 Inherited
hasOwnProperty(name:String):Boolean
Indicates whether an object has a specified property defined.
Object
 Inherited
initialized(document:Object, id:String):void
Called automatically by the MXML compiler when the Validator is created using an MXML tag.
Validator
 Inherited
isPrototypeOf(theClass:Object):Boolean
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
 Inherited
propertyIsEnumerable(name:String):Boolean
Indicates whether the specified property exists and is enumerable.
Object
 Inherited
removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void
Removes a listener from the EventDispatcher object.
EventDispatcher
 Inherited
setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
toLocaleString():String
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
toString():String
Returns the string representation of the specified object.
Object
 Inherited
validate(value:Object = null, suppressEvents:Boolean = false):ValidationResultEvent
Performs validation and optionally notifies the listeners of the result.
Validator
 Inherited
validateAll(validators:Array):Array
[static] Invokes all the validators in the validators Array.
Validator
  
validateString(validator:StringValidator, value:Object, baseField:String = null):Array
[static] Convenience method for calling a validator.
StringValidator
 Inherited
valueOf():Object
Returns the primitive value of the specified object.
Object
 Inherited
willTrigger(type:String):Boolean
Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.
EventDispatcher
Protected Methods
 MethodDefined By
 Inherited
addListenerHandler():void
Sets up all of the listeners for the valid and invalid events dispatched from the validator.
Validator
  
doValidation(value:Object):Array
[override] Override of the base class doValidation() method to validate a String.
StringValidator
 Inherited
getValueFromSource():Object
Returns the Object to validate.
Validator
 Inherited
handleResults(errorResults:Array):ValidationResultEvent
Returns a ValidationResultEvent from the Array of error results.
Validator
 Inherited
isRealValue(value:Object):Boolean
Returns true if value is not null.
Validator
 Inherited
removeListenerHandler():void
Disconnects all of the listeners for the valid and invalid events dispatched from the validator.
Validator
 Inherited
resourcesChanged():void
This method is called when a Validator is constructed, and again whenever the ResourceManager dispatches a "change" Event to indicate that the localized resources have changed in some way.
Validator
Events
Click for more information on events
 Event Summary Defined By
 Inherited
activate
[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.EventDispatcher
 Inherited
deactivate
[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.EventDispatcher
 Inherited
invalid
Dispatched when validation fails.Validator
 Inherited
valid
Dispatched when validation succeeds.Validator
Protected Constants
 ConstantDefined By
 InheritedDECIMAL_DIGITS : String = "0123456789"
[static] A String containing the decimal digits 0 through 9.
Validator
 InheritedROMAN_LETTERS : String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
[static] A string containing the upper- and lower-case letters of the Roman alphabet ("A" through "Z" and "a" through "z").
Validator
Property Detail

maxLength

property
maxLength:Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Maximum length for a valid String. A value of NaN means this property is ignored.

The default value is NaN.



Implementation
    public function get maxLength():Object
    public function set maxLength(value:Object):void

minLength

property 
minLength:Object

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Minimum length for a valid String. A value of NaN means this property is ignored.

The default value is NaN.



Implementation
    public function get minLength():Object
    public function set minLength(value:Object):void

tooLongError

property 
tooLongError:String

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Error message when the String is longer than the maxLength property.

The default value is "This string is longer than the maximum allowed length. This must be less than {0} characters long.".



Implementation
    public function get tooLongError():String
    public function set tooLongError(value:String):void

tooShortError

property 
tooShortError:String

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Error message when the string is shorter than the minLength property.

The default value is "This string is shorter than the minimum allowed length. This must be at least {0} characters long.".



Implementation
    public function get tooShortError():String
    public function set tooShortError(value:String):void
Constructor Detail

StringValidator

()Constructor
public function StringValidator()

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Constructor.

Method Detail

doValidation

()method
override protected function doValidation(value:Object):Array

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Override of the base class doValidation() method to validate a String.

You do not call this method directly; Flex calls it as part of performing a validation. If you create a custom Validator class, you must implement this method.

Parameters

value:Object — Object to validate.

Returns
Array — An Array of ValidationResult objects, with one ValidationResult object for each field examined by the validator.

validateString

()method 
public static function validateString(validator:StringValidator, value:Object, baseField:String = null):Array

Language Version: ActionScript 3.0
Product Version: Flex 3
Runtime Versions: Flash Player 9, AIR 1.1

Convenience method for calling a validator. Each of the standard Flex validators has a similar convenience method.

Parameters

validator:StringValidator — The StringValidator instance.
 
value:Object — A field to validate.
 
baseField:String (default = null) — Text representation of the subfield specified in the value parameter. For example, if the value parameter specifies value.mystring, the baseField value is "mystring".

Returns
Array — An Array of ValidationResult objects, with one ValidationResult object for each field examined by the validator.

See also

mx.validators.ValidationResult
Examples (  How to use this example  )
StringValidatorExample.mxml
<?xml version="1.0" encoding="utf-8"?>
<!-- Simple example to demonstrate StringValidator. -->
<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">

    <fx:Script>
        import mx.controls.Alert;
    </fx:Script>

    <fx:Declarations>
        <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!');"
                invalid="Alert.show('Validation Failed!');"/>
    </fx:Declarations>

    <s:Panel title="StringValidator Example"
            width="75%" height="75%"
            horizontalCenter="0" verticalCenter="0">
        <mx:Form left="10" right="10" top="10" bottom="10">
                <mx:FormItem label="Enter a name between 4 and 20 characters: ">
                    <s:TextInput id="fname" width="100%"/>
                </mx:FormItem>
                <mx:FormItem >
                    <s:Button id="myButton" label="Validate" />
                </mx:FormItem>
        </mx:Form>
    </s:Panel>

</s:Application>



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Fri Mar 19 2010, 02:45 AM -07:00