yii2 - dynamicform wbraganca：我的代码出了什么问题

在我提交请求后，它会变为空白页面 . 请检查我的代码 . 谢谢 . 我正在使用yii2框架和wbraganca动态表单插件 .

public function actionCreate()
    {
        $model = new PurchaseOrder();
        $details = [ new PurchaseOrderDetail ];

        $seq = Sequence::findOne(['id' => 'PO', 'name' => (int)date('ymd')]);
        if(is_null($seq)){
            $_seq = new Sequence();
            $_seq->id = 'PO';
            $_seq->name = (int)date('ymd');
            $_seq->value = 0;
            $_seq->save();
            $model->id = $_seq->id . '/' . $_seq->name . '/' .str_pad($_seq->value+1, 3, "0", STR_PAD_LEFT);
        }
        else {
            $seq->value += 1;
            $model->id = $seq->id . '/' . $seq->name . '/' . str_pad($seq->value, 3, "0", STR_PAD_LEFT);
            $seq->update();
        }
        $model->trx_date = date('Y-m-d');

        if ($model->load(Yii::$app->request->post())) {
            $details = Model::createMultiple(PurchaseOrderDetail::classname());
            Model::loadMultiple($details, Yii::$app->request->post());

            //assign po_id
            foreach($details as $detail){
                $detail->oid = uniqid();
                $detail->po_id = 0;
            }

            // ajax validation
            if(Yii::$app->request->isAjax){
                Yii::$app->response->format = Response::FORMAT_JSON;
                return ArrayHelper::merge(
                    ActiveForm::validateMultiple($details),
                    ActiveForm::validate($model)
                );
            }

            // validate all models
            $valid1 = $model->validate();
            $valid2 = Model::validateMultiple($details);
            $valid = $valid1 && $valid2;

            if($valid){
                $trx = \Yii::$app->db->beginTransaction();
                try
                {
                    // save master record
                    if($flag = $model->save(false)){
                        // save detail records
                        foreach($details as $detail){
                            $detail->po_id = $model->id;
                            if(!($flag = $detail->save(false))){
                                $trx->rollBack();
                                break;
                            }
                        }                       
                    }
                    if($flag){
                        //if success commit transaction
                        //then view the result
                        $trx->commit();
                        return $this->redirect(['view', 'id' => $model->id]);
                    } else {
                        return $this->render('create', [
                            'model' => $model,
                            'details' => $details
                        ]);
                    } 
                }
                catch(Exception $ex){
                    // transaction failed, rollBack
                    $trx->rollBack();
                    throw $ex;
                }
            }                       
        } else {
            return $this->render('create', [
                'model' => $model,
                'details' => $details
            ]);
        }
    }

当我单击创建按钮，它重定向到空白页，我检查日志，它没有生成任何错误日志 . 这是日志

Routing
Name    Value
Route   'purchase-order/create'
Action  'app\\controllers\\PurchaseOrderController::actionCreate()'
Parameters  []
$_GET
Empty.

$_POST
Name    Value
_csrf   'a0hCeHJoLXEbEgY.C15vXD0ydBEiLVsVPSQ2OUQSdQs0MCoTHw1qQg=='
PurchaseOrder   [
    'id' => 'PO/170407/024'
    'trx_date' => '2017-04-07'
    'supplier_id' => '1'
    'remark' => 'test remark'
    'total' => '1500000'
]
PurchaseOrderDetail [
    0 => [
        'item_id' => '1'
        'qty' => '10'
        'price' => '150000'
        'total' => '1500000'
        'remark' => 'aa'
    ]
]
$_FILES
Empty.

$_COOKIE
Name    Value
_csrf   'c3c290ca6c2fdb8a905c1692baebc21ba6a5715325855d6e863a91f1cd5cd5c7a:2:{i:0;s:5:\"_csrf\";i:1;s:32:\"pZDFy6B-Vz6iPEvdVltA6zXz_xhkmeG3\";}'
PHPSESSID   'o1337j64mptbjhptr2o3dcl5k7'
Request Body
Name    Value
Content Type    'application/x-www-form-urlencoded'
Raw '_csrf=a0hCeHJoLXEbEgY.C15vXD0ydBEiLVsVPSQ2OUQSdQs0MCoTHw1qQg%3D%3D&PurchaseOrder%5Bid%5D=PO%2F170407%2F024&PurchaseOrder%5Btrx_date%5D=2017-04-07&PurchaseOrder%5Bsupplier_id%5D=1&PurchaseOrder%5Bremark%5D=test+remark&PurchaseOrderDetail%5B0%5D%5Bitem_id%5D=1&PurchaseOrderDetail%5B0%5D%5Bqty%5D=10&PurchaseOrderDetail%5B0%5D%5Bprice%5D=150000&PurchaseOrderDetail%5B0%5D%5Btotal%5D=1500000&PurchaseOrderDetail%5B0%5D%5Bremark%5D=aa&PurchaseOrder%5Btotal%5D=1500000'
Decoded to Params   [
    '_csrf' => 'a0hCeHJoLXEbEgY.C15vXD0ydBEiLVsVPSQ2OUQSdQs0MCoTHw1qQg=='
    'PurchaseOrder' => [
        'id' => 'PO/170407/024'
        'trx_date' => '2017-04-07'
        'supplier_id' => '1'
        'remark' => 'test remark'
        'total' => '1500000'
    ]
    'PurchaseOrderDetail' => [
        0 => [
            'item_id' => '1'
            'qty' => '10'
            'price' => '150000'
            'total' => '1500000'
            'remark' => 'aa'
        ]
    ]
]

请帮忙 . 谢谢你