flex 下拉框验证组件

//继承验证

public class ObjectNullValidator extends Validator
 {
  public function ObjectNullValidator()
  {
   super();
   requiredFieldError = "必须填写" ;
  }
    
  private var _invalidCode:String = "222";
  
  public static function validateString(validator:ObjectNullValidator, value:Object, baseField:String = null, aa:Boolean = false):Array
  {
   var results:Array = [];
   if (!aa)
   {
    if (value==null)
     results.push(new ValidationResult(true, baseField, "222", validator.requiredFieldError));
   }
   return results;
  }
  
  override protected function doValidation(value:Object):Array
  {
   var results:Array = super.doValidation(value);
   var val:String = value ? String(value) : "";
   if (results.length > 0 || ((val.length == 0) && !required))
    return results;
   else
    return ObjectNullValidator.validateString(this, value, null, required );
  }
  
  public function get invalidCode():String
  {
   return _invalidCode;
  }

 }

 

//组件调用

<valid:ObjectNullValidator source="{_setmeal}"
             property="selectedItem"
             required = "true"
             requiredFieldError = "(必选项)"
             triggerEvent = "focusOut"/>