php - Laravel 中类 'modelName' 的对象无法转换为 int

Question

我正在尝试创建一个类似于 - HCL/LF/02/2018 的发票编号，其中新发票的编号将增加 1。有人可以帮我获得预期的invoice_no吗？我在我的 Controller 中尝试了类似的操作 -

public function create()
{
    $check = OrderProformaInvoice::orderBy('created_at', 'DESC')->get();
    $number = 01;
    $year   = date('Y');
    if (count($check) > 0) {

        $invoiceNo = OrderProformaInvoice::latest()->first(['invoice_no']);

        $arr     = array('HCL','LF', $invoiceNo + 1, $year);
        $newInvoiceNo = implode("/",$arr);
    }else{

        $arr     = array('HCL','LF', $number, $year);
        $newInvoiceNo = implode("/",$arr);

    }
    return view('admin.marchendaising.order-proforma-invoices.create', compact('newInvoiceNo'));
}

在我看来，表单输入字段是 -

<input type="text" name="invoice_no" class="form-control" value="{{ $newInvoiceNo }}">

Answer 1

您在这行中有错误:

$invoiceNo = OrderProformaInvoice::latest()->first(['invoice_no']);

正确:

$invoiceNo = OrderProformaInvoice::latest()->get()->invoice_no;