取决于默认CakePHP下拉

Question

在创建发票时，我希望能够根据所选客户本国货币设置下拉货币列表的默认值，但我仍希望能够通过选择其他货币来更改此默认值。

例如，我的货币表包含所有可用货币

客户表格及其首选货币。

最后是使用货币的发票表

例如，当选择此客户时，我希望货币更改为澳元，但我仍希望能够更改它。

不太确定从哪里开始我可以提供任何线索，非常感谢。

这是我的观看文件add.ctp

的代码

<div class="invoices form large-9 medium-8 columns content">
    <?= $this->Form->create($invoice) ?>
    <fieldset>
        <legend><?= __('Add Invoice') ?></legend>
        <?php
            echo $this->Form->input('customer_id', ['options' => $customers, 'empty' => true,'id'=>'customers']);
            echo $this->Form->input('currency_id', ['options' => $currencies, 'default'=> 1]);
        ?>

    </fieldset>
    <?= $this->Form->button(__('Submit')) ?>
    <?= $this->Form->end() ?>
</div>

这是我在InvoiceController中的添加功能。

public function add()
    {
        $invoice = $this->Invoices->newEntity();
        if ($this->request->is('post')) {
            $invoice = $this->Invoices->patchEntity($invoice, $this->request->data);
            if ($this->Invoices->save($invoice)) {
                $this->Flash->success(__('The invoice has been saved.'));

                return $this->redirect(['action' => 'index']);
            }
            $this->Flash->error(__('The invoice could not be saved. Please, try again.'));
        }
        $customers = $this->Invoices->Customers->find('list', ['limit' => 200]);
        $currencies = $this->Invoices->Currencies->find('list', ['limit' => 200]);

        $this->set(compact('invoice', 'customers', 'users', 'customerContacts', 'aircraftRegistrations', 'shippingCompanies', 'supervisingEngineerUsers', 'jobTypes', 'openedByUsers', 'assignedToUsers', 'currencies'));
        $this->set('_serialize', ['invoice']);
    }