// 查询上下篇

        $courseIds = model('course')

            ->where([

                'isdel' => 0,

                'teacherid' => $teacher['id'],

                'ispublic' => 1

            ])

            ->order('sort desc')

            ->order('view desc')

            ->column('id');

        $cidKey = array_search($cid, $courseIds);

        $preCourseId = array_key_exists($cidKey+1, $courseIds) ? $courseIds[($cidKey +1)] : false;

        $nexCourseId = array_key_exists($cidKey-1, $courseIds) ? $courseIds[($cidKey -1)] : false;

        $this->assign([

            'course' => $course,

            'preCourseId' => $preCourseId,

            'nexCourseId' => $nexCourseId,

            'model' => new CourseModel

        ]);

{{if condition="$preCourseId !== false"}}

<div>

     <span class="font-bold">上一篇：</span><a href="{{:url('index/teacher/cindex', ['cid' => $preCourseId])}}">{{$model->get($preCourseId)['title']}}</a>

</div>

{{/if}}

{{if condition="$nexCourseId !== false"}}

<div>

    <span class="font-bold">下一篇：</span><a href="{{:url('index/teacher/cindex', ['cid' => $nexCourseId])}}">{{$model->get($nexCourseId)['title']}}</a>

</div>

{{/if}}