存储关联表车辆数据时触发Undefined variable $fleet错误

在向与fleets表存在关联关系的vehicles表存储数据时，点击添加新车辆按钮时无报错，但尝试将数据存入数据库时，触发ErrorException，提示「Undefined variable $fleet」。

视图代码 #

<div class="col-3">
    <label for="fleet_id" class="form-label"> Type </label>
    <select id="fleet_id" name="fleet_id" required="required" class="form-control">
        <option value="" disabled selected>Type</option>
        <?php foreach ($fleet as $value) : ?>
            <option value="<?= $value->id ?>"><?= $value->type ?></option>
        <?php endforeach ?>
    </select> 
</div>

控制器代码 #

public function new()
{
    $data['fleet'] = $this->fleetModel->findAll();
    $data['module'] = lang("Localize.fleet") ; 
    $data['title'] = lang("Localize.add_vehicle") ;
    $data['pageheading'] = lang("Localize.add_vehicle");
    echo view($this->Viewpath . '\vehical/new', $data);
}
    
public function create()
{
    $imgpath = array(); 
    $imgbus = $this->request->getFileMultiple('busimg');

    if (!empty($imgbus)) {
        foreach ($imgbus as $key => $imgvalue) {
            if ($imgvalue->isValid() && !$imgvalue->hasMoved()) {
                $busimag = $this->imgaeCheck($imgvalue);
                array_push($imgpath, $busimag);
            }
        }
    }

    $data = array(
        "fleet_id" => $this->request->getVar('fleet_id'),
        "reg_no" => $this->request->getVar('reg_no'),
        //  "engine_no" => $this->request->getVar('engine_no'),
        //  "model_no" => $this->request->getVar('model_no'),
        //  "chasis_no" => $this->request->getVar('chasis_no'),
        "woner" => $this->request->getVar('woner'),
        "woner_mobile" => $this->request->getVar('woner_mobile'),
        "company" => $this->request->getVar('company'),
        "status" => $this->request->getVar('status'),
        "assign" => $this->request->getVar('assign'),
    );

    if ($this->validation->run($data, 'vehical')) {
        $vehicleid = $this->vehiclModel->insert($data);
        if (!empty($imgpath)) {
            foreach ($imgpath as $key => $imgvalue) {
                $storedata[$key] = array(
                    "vehicle_id" => $vehicleid,
                    "img_path" => $imgvalue,
                );
            }
            $this->vImageModel->insertBatch($storedata);
        }
        return redirect()->route('index-vehicle')->with("success", "Data Save");
    } else {
        $data['validation'] = $this->validation;
        $data['module'] = lang("Localize.fleet"); 
        $data['title'] = lang("Localize.add_vehicle");
        echo view($this->Viewpath . '\vehical/new', $data);
    }
}

问题原因 #

问题出在create方法的表单验证失败分支（else块）：当表单验证不通过时，你重新渲染了添加车辆的视图，但没有像new方法那样将$fleet数据传入视图。视图中的下拉选择框需要遍历$fleet变量生成选项，变量缺失就会触发「Undefined variable $fleet」错误。

修复方案 #

在create方法的else块中，添加获取fleet数据的代码，确保渲染视图时包含该变量：

} else {
    // 新增这一行，获取fleet数据
    $data['fleet'] = $this->fleetModel->findAll();
    $data['validation'] = $this->validation;
    $data['module'] = lang("Localize.fleet"); 
    $data['title'] = lang("Localize.add_vehicle");
    echo view($this->Viewpath . '\vehical/new', $data);
}

这样当验证失败返回表单时，视图就能拿到$fleet变量，下拉框可以正常渲染，错误就会消失。

内容的提问来源于stack exchange，提问作者muhammed alsmawi