API调用移至Controller后视图国家下拉框无法加载问题排查

核心原因 #

你把API请求移到Controller后，create.php渲染_form.php时没有将$countries变量传递给子视图，导致_form.php里的$countries未定义，触发了No countries found的分支。

解决方案 #

1. 修改create.php，传递变量给子视图 #

确保create.php在渲染_form.php时，把Controller传来的$countries（或处理后的列表）一并传递：

<?php
// create.php中的渲染代码
echo $this->render('_form', [
    'model' => $model,
    'countries' => $countries, // 新增此行，传递国家数据
]);
?>

2. 清理_form.php，移除冗余代码 #

删除_form.php中原有的API请求代码，直接使用传递过来的$countries变量：

<div class="card styled-card">
    <div class="card-body">
        <div class="people-form">
            <?php $form = ActiveForm::begin(); ?>

            <!-- 其他表单字段代码 -->

            <?php
            if (!empty($countries)):
                $countryList = [];
                foreach ($countries as $country) {
                    if (isset($country['name']['common'])) {
                        $countryList[] = $country['name']['common'];
                    }
                }
                
                asort($countryList);
                ?>
                <?= $form->field($model, 'nation')->dropDownList(
                    array_combine($countryList, $countryList),
                    ['prompt' => 'Select a Country']
                )->label('Nation') ?>
            <?php else: ?>
                <p>No countries found.</p>
            <?php endif; ?>

            <!-- 提交按钮代码 -->

            <?php ActiveForm::end(); ?>
        </div>
    </div>
</div>

优化建议（可选，更符合MVC规范） #

可以直接在Controller中处理国家列表的格式化和排序，减少视图层的逻辑：

修改后的actionCreate方法 #

public function actionCreate()
{
    $model = new People();

    // 调用API获取国家数据
    $curl = curl_init();
    curl_setopt_array($curl, array(
        CURLOPT_URL => 'https://restcountries.com/v3.1/all?fields=name',
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_ENCODING => '',
        CURLOPT_MAXREDIRS => 10,
        CURLOPT_TIMEOUT => 0,
        CURLOPT_FOLLOWLOCATION => true,
        CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
        CURLOPT_CUSTOMREQUEST => 'GET',
    ));
    $response = curl_exec($curl);
    curl_close($curl);
    $countries = json_decode($response, true);

    // 提前处理国家列表
    $countryList = [];
    if (!empty($countries)) {
        foreach ($countries as $country) {
            if (isset($country['name']['common'])) {
                $countryList[] = $country['name']['common'];
            }
        }
        asort($countryList);
    }

    // 表单提交逻辑
    if ($this->request->isPost) {
        if ($model->load($this->request->post()) && $model->save()) {
            return $this->redirect(['view', 'id' => $model->id]);
        }
    } else {
        $model->loadDefaultValues();
    }

    // 传递处理后的列表给视图
    return $this->render('create', [
        'model' => $model,
        'countryList' => $countryList,
    ]);
}

对应的create.php传递代码 #

<?php
echo $this->render('_form', [
    'model' => $model,
    'countryList' => $countryList,
]);
?>

简化后的_form.php国家选择部分 #

<?php
if (!empty($countryList)):
    ?>
    <?= $form->field($model, 'nation')->dropDownList(
        array_combine($countryList, $countryList),
        ['prompt' => 'Select a Country']
    )->label('Nation') ?>
<?php else: ?>
    <p>No countries found.</p>
<?php endif; ?>

内容的提问来源于stack exchange，提问作者chickenzz