我试图弄清楚如何在Laravel中使用ajax，jquery获得特定年份的所有主题。
我在数据库中有三个表：
years: id, name
subjects: id, name
year_subject: id, year_id , subject_id
这些是模型：
Year.php
Subject.php
YearSubject.php
这是控制器中的功能
public function get_subjects($id)
{
$sub = YearSubject::where("year_id", $id)->pluck("subject_id");
$subjects=Subject::where('$id',$sub)->pluck('name','id');
foreach($sub as $s)
{
$subjects= Subject::where('$id',$s)->pluck('name','id');
}
return json_encode($subjects);
}
<script type="text/javascript">
$(document).ready(function () {
$('#grade').on('change', function () {
var gradeID = $(this).val();
$('#subject').empty();
if (gradeID) {
$.ajax({
url: '{{url('get_subjects')}}' + '/' + gradeID,
type: "GET",
dataType: "json",
success: function (data) {
$.each(data, function (key, value) {
$('#subject').append('<option value="' + key + '">' + value + '</option>');
});
}
});
} else {
$('#subject').empty();
}
});
});
</script> <select id="grade" name="grade" required>
<option value="" disabled selected> Choose Year</option>
@foreach($grades as $grade)
<option value="{{$grade->id}}">{{$grade->name}}</option>
@endforeach
</select>
<select name="subject" id="subject" >
<option value="">Choose Subject </option>
</select>这是路线
Route::get('get_subjects/{id}', 'SubjectController@get_subjects')->name('get_subjects');
我猜错误是在控制器上。无法弄清楚如何在$ subjects处推送值。
最佳答案
将模型更改为如下所示-
Year.php
class Year extends Model{
public $primaryKey = 'id';
public $timestamps = true;
protected $table = 'years';
public function subjects(){
return $this->belongsToMany('year_subject','year_id','subject_id');
}
}
Subject.php
class Subject extends Model{
public $primaryKey = 'id';
public $timestamps = true;
protected $table = 'subjects';
public function years(){
return $this->belongsToMany('year_subject','subject_id','year_id');
}
}
您的控制器方法：
public function get_subjects($year_id){
$subject_data = [];
foreach(Year::where('id',$year_id)->subjects() as $each_subject_data){
$subject_data[] = [
'subject_id' => $each_subject_data->id,
'subject_name' => $each_subject_data->name
];
}
return response(json_encode($subject_data),200)
->header('Content-Type','application/json');
}
注意：您可以检查元素并在浏览器的“网络”选项卡中检查要接收的JSON，并相应地在控制器方法中修改所需的JSON格式。
关于javascript - Laravel，无法弄清楚如何通过下拉菜单显示特定年份的主题，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/52345580/