依赖下拉错误不能在Yii中留空

我在yii中做了2个依赖的下拉菜单，它工作得很好。但是，即使从下拉列表中选择值，当我提交(创建)表单时，它显示以下错误:请修正以下输入错误:Taluk不能是空白的。"地区"不能为空。

和值没有插入到数据库中。我遵循了使用AJAX和创建依赖下拉列表的简单解决方案中给出的一切

下面是我在view(_form.php)中的代码:

<div class="row"> 
    <?php                                   
        echo CHtml::dropDownList('district_id','',
        array(4=>'Gulbarga',3=>'Bangalore Urban'),
        array(
            'prompt'=>'Select District',
            'ajax' => array(
                'type'=>'POST', 
                'url'=>CController::createUrl('loadTaluk'),
                'update'=>'#taluk_id', 
                'data'=>array('district_id'=>'js:this.value'),
            ))); 
            echo CHtml::dropDownList('taluk_id','', array(), array('prompt'=>'Select a Taluk'));
    ?>
</div>

在我的InquiriesController:

public function actionLoadTaluk()
    {
        $data=Taluk::model()->findAll('district_id=:district_id',
        array(':district_id'=>(int) $_POST['district_id']));
        $data=CHtml::listData($data,'taluk_id','name');
        echo "<option value=''>Select a Taluk</option>";
        foreach($data as $value=>$name)
        echo CHtml::tag('option', array('value'=>$value),CHtml::encode($name),true);
    }

这是我的模型(queries .php):

<?php
public function rules()
    {   
        return array(
            array('organization, aplication_type, contact_person, pan, city_town_village, taluk_id, district_id', 'required'),
            array('organization, email', 'length', 'max'=>200),
            array('aplication_type, contact_person, pan', 'length', 'max'=>100),
            array('phone', 'length', 'max'=>60),
            array('address', 'length', 'max'=>150),
            array('pin_code', 'length', 'max'=>6),
            array('city_town_village', 'length', 'max'=>128),
            array('taluk_id, district_id', 'length', 'max'=>10),
            array('inquiry_id, organization, aplication_type, contact_person, email, phone, pan, address, pin_code, city_town_village, taluk_id, district_id', 'safe', 'on'=>'search'),
        );
    }
public function relations()
    {
        return array(
            'taluk' => array(self::BELONGS_TO, 'Taluk', 'taluk_id'),
        );
    }
public function attributeLabels()
    {
        return array(
            'inquiry_id' => 'Inquiry',
            'organization' => 'Organization',
            'aplication_type' => 'Aplication Type',
            'contact_person' => 'Contact Person',
            'email' => 'Email',
            'phone' => 'Phone',
            'pan' => 'Pan',
            'address' => 'Address',
            'pin_code' => 'Pin Code',
            'city_town_village' => 'City Town Village',
            'taluk_id' => 'Taluk',
            'district_id' => 'District',
        );
    }
public function search()
    {
        $criteria=new CDbCriteria;
        $criteria->compare('inquiry_id',$this->inquiry_id,true);
        $criteria->compare('organization',$this->organization,true);
        $criteria->compare('aplication_type',$this->aplication_type,true);
        $criteria->compare('contact_person',$this->contact_person,true);
        $criteria->compare('email',$this->email,true);
        $criteria->compare('phone',$this->phone,true);
        $criteria->compare('pan',$this->pan,true);
        $criteria->compare('address',$this->address,true);
        $criteria->compare('pin_code',$this->pin_code,true);
        $criteria->compare('city_town_village',$this->city_town_village,true);
        $criteria->compare('taluk_id',$this->taluk_id,true);
        $criteria->compare('district_id',$this->district_id,true);
        return new CActiveDataProvider($this, array(
            'criteria'=>$criteria,
        ));
    }
public static function model($className=__CLASS__)
    {
        return parent::model($className);
    }
}

谁来帮帮我…

<div class="row"> 
        <?php                                   
  echo CHtml::dropDownList('Inquiries[district_id]','',
  array(4=>'Gulbarga',3=>'Bangalore Urban',5=>'Bangalore Rural'),
  array(
    'prompt'=>'Select District',
    'ajax' => array(
    'type'=>'POST', 
    'url'=>CController::createUrl('loadTaluk'), //or $this->createUrl('loadcities') if '$this' extends CController
    'update'=>'#Inquiries_taluk_id', //or 'success' => 'function(data){...handle the data in the way you want...}',
  'data'=>array('district_id'=>'js:this.value'),
  ))); 

echo CHtml::dropDownList('Inquiries[taluk_id]','', array(), array('prompt'=>'Select a Taluk'));
?>
    </div>

echo CHtml::dropDownList('Inquiries[district_id]','', 
'update'=>'#Inquiries_taluk_id',