本文实例讲述了Yii2使用dropdownlist实现地区三级联动功能的方法。分享给大家供大家参考，具体如下：

视图部分：

<?php
use yiihelpersUrl;
use yiiwidgetsActiveForm;
use yiihelpersArrayHelper;
use yiihelpersHtml;
/* @var $this yiiwebView */
/* @var $model commonsearchserviceItemSearch */
/* @var $form yiiwidgetsActiveForm */
?>
<div class="row">
  <div class="item-search">
    <?php $form = ActiveForm::begin([
      'action' => ['index'],
      'method' => 'get',
      'options' => ['class' => 'form-inline']
    ]); ?>
    <?= $form->field($model, 'cityName', ['options' => ['class' => 'form-group col-lg-2']])->dropDownList(ArrayHelper::map($cities, 'id', 'name'), ['prompt' => '请选择城市'])->label('请选择城市', ['class' => 'sr-only']) ?>
    <?= $form->field($model, 'areaName', ['options' => ['class' => 'form-group col-lg-2']])->dropDownList(ArrayHelper::map($areas, 'id', 'name'), ['prompt' => '请选择区县'])->label('请选择区县', ['class' => 'sr-only']) ?>
    <?= $form->field($model, 'communityName', ['options' => ['class' => 'form-group col-lg-2']])->dropDownList(ArrayHelper::map($communities, 'id', 'name'), ['prompt' => '请选择小区'])->label('请选择小区', ['class' => 'sr-only']) ?>
    <div class="col-lg-2 col-lg-offset-1">
      <input class="form-control" id="keyword" placeholder="请输入小区名" value="" />
    </div>
    <div class="col-lg-1">
      <button type="button" id="search-community" class="btn btn-info">搜索</button>
    </div>
    <p></p>
    <div class="form-group col-lg-1 pull-right">
      <?= Html::submitButton('搜索', ['class' => 'btn btn-primary']) ?>
    </div>
    <?php ActiveForm::end(); ?>
  </div>
</div>
<p> </p>
<?php
$this->registerJs('
  //市地址改变
  $("#itemsearch-cityname").change(function() {
    //市id值
    var cityid = $(this).val();
    $("#itemsearch-areaname").html("<option value="0">请选择区县</option>");
    $("#itemsearch-communityname").html("<option value="0">请选择小区</option>");
    if (cityid > 0) {
      getArea(cityid);
    }
  });
  //区地址改变
  $("#itemsearch-areaname").change(function() {
    //区id值
    var areaid = $(this).val();
    $("#itemsearch-communityname").html("<option value="0">请选择小区</option>");
    if (areaid > 0) {
      getCommunity(areaid);
    }
  });
  //获取市下面的区列表
  function getArea(id)
  {
    var href = "http://www.gimoo.net/t/1811/5bf6620220c9b.html' . Url::to(['/service/base/get-area-list'], true). '";
    $.ajax({
      "type" : "GET",
      "url"  : href,
      "data" : {id : id},
      success : function(d) {
        $("#itemsearch-areaname").append(d);
      }
    });
  }
  //获取区下面的小区列表
  function getCommunity(id)
  {
    var href = "http://www.gimoo.net/t/1811/5bf6620220c9b.html' . Url::to(['/service/base/get-community-list'], true) . '";
    $.ajax({
      "type" : "GET",
      "url"  : href,
      "data" : {id : id},
      success : function(d) {
        $("#itemsearch-communityname").append(d);
      }
    });
  }
  //搜索小区
  $("#search-community").click(function() {
    var word  = $("#keyword").val();
    var areaid = $("#itemsearch-areaname option:selected").val();
    var href  = "http://www.gimoo.net/t/1811/5bf6620220c9b.html' . Url::to(['/service/base/search-community'], true) . '";
    if (areaid > 0) {
      $.ajax({
        "type" : "GET",
        "url"  : href,
        "data" : {id : areaid, word : word},
        success : function(d) {
          $("#itemsearch-communityname").html(d);
        }
      });
    }
  });
');
?>

模型部分：

就是我们常用的ajax请求,当然php中需要直接组合成<option value=""></option>这样的结构直接用,$form->field($model, $var)中的变量数据表中不一定有,得在模型中自己定义,并设置安全字段,而且搜索模型也可能需要修改成自己需要的样子,模型可能要这样：

class HuangYeError extends yiidbActiveRecord
{
  public $cityName;
  public $areaName;
  public $communityName;
  public $group;
  public $cate;
  /**
   * @inheritdoc
   */
  public static function tableName()
  {
    return 'll_hy_huangye_error';
  }
  public static function getDb()
  {
    return Yii::$app->get('dbnhuangye');
  }
}

之前是多表,需要使用jjoinWith()连表,后来被我全部转化为单表了,多表实在是慢,能转化成单表就用单表吧：

class HuangYeErrorSearch extends HuangYeError
{
  const PAGE_SIZE = 20;
  public $communityName;
  public $startTime;
  public $endTime;
  /**
   * @inheritdoc
   */
  public function rules()
  {
    return [
      [['id', 'serviceid', 'userid', 'categoryid', 'communityid', 'sortorder', 'ctime', 'utime', 'status'], 'integer'],
      [['username', 'name', 'logo', 'phone', 'address', 'content', 'error', 'communityName', 'startTime', 'endTime'], 'safe'],
    ];
  }
  /**
   * @inheritdoc
   */
  public function scenarios()
  {
    // bypass scenarios() implementation in the parent class
    return Model::scenarios();
  }
  /**
   * Creates data provider instance with search query applied
   *
   * @param array $params
   *
   * @return ActiveDataProvider
   */
  public function search($params)
  {
    $query = HuangYeError::find();
    //status == 9 删除状态
    $condition = ' `status` != :status';
    $p[':status'] = 9;
    $query->where($condition, $p);
    $dataProvider = new ActiveDataProvider([
      'query' => $query,
      'pagination' => [
        'pageSize' => self::PAGE_SIZE,
      ],
    ]);
    $this->load($params);
    if (!$this->validate()) {
      // uncomment the following line if you do not want to any records when validation fails
      // $query->where('0=1');
      return $dataProvider;
    }
    $query->andFilterWhere([
      'userid' => $this->userid
    ]);
    $query->andFilterWhere(['like', 'username', $this->username])
      ->andFilterWhere(['like', 'name', $this->name])
      ->andFilterWhere(['like', 'phone', $this->phone])
      ->andFilterWhere(['like', 'address', $this->address])
      ->andFilterWhere(['like', 'content', $this->content])
      ->andFilterWhere(['ll_hy_huangye_error.status' => $this->status])
      ->andFilterWhere(['ll_hy_huangye_error.categoryid' => $this->categoryid])
      ->andFilterWhere(['between', 'ctime', strtotime($this->startTime . '0:0:0'), strtotime($this->endTime . '23:59:59')])
      ->andFilterWhere(['like', 'error', $this->error]);
    if (intval($this->communityName)) {
      $query->andFilterWhere(['ll_hy_huangye_error.communityid' => intval($this->communityName)]);
    }
    $order = ' `ctime` DESC';
    $query->orderBy($order);
    return $dataProvider;
  }
}

控制器中写比较简单一点,直接调用就行了：

/**
* ajax请求小区
*
* @param $id
* @return string
*/
public function actionGetCommunityList($id)
{
    $option = '';
    $result = self::getCommunity($id);
    if ($result) {
      foreach ($result as $value) {
        $option .= '<option value="' . $value['id'] . '">' . $value['name'] . '</option>';
      }
    } else {
      $option .= '<option value="0">暂未开通可选择的小区</option>';
    }
    echo $option;
}

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