public function isValid() {
        if($this->isRequired()) {
            if($this->getValue() == null) return false;
            if($this->getValue() == "") return false;
        }
        return true;
    }
public function isValid() {
        if($this->isRequired()) {
            if($this->getValue() == null) return false;
            if($this->getValue() == "") return false;
        }
        return true;
    }
public function isValid ( ) { if ( $ this -> isRequired ( ) ) { if ( $ this -> getValue ( ) == null ) return false ; if ( $ this -> getValue ( ) == "" ) return false ; } return true ; }
Validate value of control
@return boolean validation successfully?
Validate value of control