一、set_teachers.py文件
from django.shortcuts import render,redirect
from app01 import models
def set_teachers(request):
if request.method == "GET":
nid = request.GET.get("nid") # 获取后可继续传给HTML文件
cls_obj = models.Classes.objects.filter(id=nid).first()
cls_teachers_list = cls_obj.c_to_t.all().values_list("id")
# 2、先用value_list取出，再用zip函数
id_list = list(zip(*cls_teachers_list))[0] if list(zip(*cls_teachers_list)) else []
# 如果if list(zip(*cls_teachers_list))不为空则执行if前语句，为空时执行else语句
all_teachers_list = models.Teachers.objects.all()
# [obj,obj,obj]
# 1、可以直接用Queryset类型里对象判断
# for i in all_teachers_list:
# if i in cls_teachers_list
return render(request,"set_teachers.html",{
"cls_teachers_list": cls_teachers_list,
"all_teachers_list": all_teachers_list,
"id_list":id_list,
"nid":nid
})
elif request.method == "POST":
nid = request.GET.get("nid")
ids = request.POST.getlist("teacher_ids") # 获取多个值
obj = models.Classes.objects.filter(id=nid).first()
obj.c_to_t.set(ids) # 重置
return redirect("/classes.html")
二、HTML文件操作
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="/set_teachers.html?nid={{nid}}" method="POST">
{% csrf_token %}
<select name="teacher_ids" id="" multiple size="10"> {# 设置为多选和大小 #}
{% for item in all_teachers_list %} {# 列出所有老师，并通过if判断来默认选择 #}
{% if item.id in id_list %}
<option value="{{item.id}}" selected="selected">{{item.name}}</option>
{% else %}
<option value="{{item.id}}" >{{item.name}}</option>
{% endif %}
{% endfor %}
</select>
<input type="submit" value="提交">
</form>
</body>
</html>
三、展示的HTML中代码
<td>
{% for item in row.c_to_t.all %} {# 执行函数不用加括号，自动加 #}
<span>{{item.name}}</span>
{% endfor %}
</td>
总结：
关键点在于值的传送与获取，一般传ID，因为其唯一性