所以我想通过 AJAX 从我的js文件中发送我要从我的复选框中删除的数据到我的控制器。它会被传递，但是每当我用count()或array_length()检查时，长度总是1，尽管输出显示的变量多于1。
jsondata
当我使用dd dd显示时，它只显示1个数组长度

表：

<?= form_open('/delete', ['class' => 'deleteBatch']); ?>
                <div class="w-fit">
                    <div class="grid grid-cols-2 gap-x-1 m-3">
                        <button data-toggle="modal" data-target="#createModal" class="inline-flex items-center justify-center rounded-md border border-transparent bg-primary-600 px-3 py-1 text-base font-medium text-white hover:bg-primary-700">New</button>
                        <button @click="deleteCheck()" class="inline-flex items-center justify-center rounded-md border border-transparent bg-primary-600 px-3 py-1 text-base font-medium text-white hover:bg-primary-700">Delete</button>
                    </div>
                </div>
                <div class="mb-3">
                    <?php $msg = session()->getFlashdata('message') ?>
                    <?php if ($msg) { ?>
                        <?php
                        if (is_array($msg)) {
                        ?>
                            <div class="bg-red-200 w-auto bg-opacity-50 border border-red-400 text-red-700 px-3 py-2 rounded relative" role="alert">
                                <?php foreach (session()->getFlashdata('message') as $row) : ?>
                                    <p class="block sm:inline"><?= $row; ?></p>
                                    <br>
                                <?php endforeach; ?>
                            </div>
                        <?php
                        } else {
                        ?>
                            <div class="bg-green-200 w-auto bg-opacity-50 border border-green-400 text-green-700 px-3 py-2 rounded relative" role="alert">
                                <span class="block sm:inline"><?= $msg; ?></span>
                            </div>
                        <?php
                        } ?>
                    <?php
                    } ?>
                </div>
                <div id='table'>
                    <table id="example" class="table-auto border-2 border-gray-400 cell-border">
                        <thead class="bg-gray-400">
                            <tr class="text-black">
                                <th>
                                    <input id="selectAll" name="selectAll " type="checkbox">
                                </th>
                                <th>Action</th>
                                <th>Project Name</th>
                                <th>Client</th>
                                <th>Project Start</th>
                                <th>Project End</th>
                                <th>Status</th>
                            </tr>
                        </thead>
                        <tbody class="text-black">
                            <?php //dd($project);
                            ?>
                            <?php foreach ($project as $row) : ?>
                                <tr>
                                    <td><input class="selectId" name="selectId" value="<?= $row->project_id; ?>" type="checkbox"><?= $row->project_id; ?></td>
                                    <td><a href="/edit">edit</a></td>
                                    <td><span id="projectName" name="projectName"><?= $row->project_name; ?></span></td>
                                    <td><span id="clientName" name="clientName"><?= $row->client_name; ?></span></td>
                                    <td id="dateProjectStart"><span id="dateProjectStart" name="dateProjectStart">{{translateMonth(<?= strtotime($row->project_start); ?>)}}</span></td>
                                    <td id="dateProjectEnd"><span id="dateProjectEnd" name="dateProjectEnd">{{translateMonth(<?= strtotime($row->project_end); ?>)}}</span></td>
                                    <td><span id="projectStatus" name="projectName"><?= $row->project_status; ?></span></td>
                                </tr>
                            <?php endforeach; ?>
                        </tbody>
                    </table>
                    <p>{{message}}</p>
                </div>
                <?= form_close(); ?>

the js（im using vue.js）：

const crud = Vue.createApp({
    data(){
        return{
            'project_id' : "",

        }
    },
    methods:{
        create(e){
            // console.log('hello')
            document.getElementById("createForm").submit();
        },
        translateMonth(date){
            const date2 = new Date(date*1000)
            const month = ["Jan","Feb","Mar", "Apr","Mei", "Jun","Jul", "Agu","Sep","Oct","Nov","Dec"]
            const dateFinal = date2.getDate() + ' ' + month[date2.getMonth()] + ' ' + date2.getFullYear()
            return dateFinal
        },
        deleteCheck(e){
            $('.deleteBatch').submit(function(e){
                e.preventDefault();

                let dataCount = $('.selectId:checked');
                if(dataCount.length == 0){
                    Swal.fire({
                        icon: 'warning',
                        title: 'Warning',
                        text: 'Please select at least one project',
                        confirmButtonText: 'Ok',
                        confirmButtonColor: '#2563eb',
                    })
                }else{
                    Swal.fire({
                            title: 'Are you sure you want to delete this project?',
                            text: dataCount.length + ' project will be deleted',
                            reverseButtons: true,
                            showCancelButton: true,
                            denyButtonText: `No`,
                            denyButtonColor: '#64748B',
                            confirmButtonText: 'Yes',
                            confirmButtonColor: '#2563eb',
                          }).then((result) => {
                            /* Read more about isConfirmed, isDenied below */
                            if (result.isConfirmed) {
                                $.ajax({
                                    type: "post",
                                    url: '/delete',
                                    dataType: 'json',
                                    data: $(this).serialize(),
                                    success:function(response){
                                        if (response.status == 200){
                                            Swal.fire({
                                                icon: 'success',
                                                title: 'Project deleted successfully',
                                                confirmButtonText: 'Ok',
                                                confirmButtonColor: '#2563eb',
                                            })
                                            window.location.replace('/project')
                                        }
                                    }

                                })
                            } else if (result.isDenied) {
                              Swal.fire('Changes are not saved', '', 'info')
                            }
                          })
                }
                return false;
            })
            // 
            
        }

    }
})
crud.mount('#crud')

控制器：

public function delete()
    {
        $session = \Config\Services::session();
        $projectModel = new ProjectModel();
        $selectedId = $this->request->getVar('selectId');
        $data = [
            'selectId' => $selectedId
        ];
        $dataCount = count($data);
        dd($dataCount);
    }

我已经改变了$this->request->getVar('selectId');到$this->request->getPost('selectId')仍然没有运气，已经尝试了json_decode太，但仍然相同