Django 检查用户是否在多个字段中

我有以下带有m2m字段的模型，登录用户可以在其中显示对出版物的兴趣：

型号.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

视图.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

现在，当登录用户已经对出版物感兴趣时，我尝试在模板中生成“我已经感兴趣”：

base.html

{% for publication in publications %}

  {{publication.title}}

  {% if currently logged in User is interested in publication (check users_interested) %}
      i am already interested
  {% endif %}

{% endfor %}

{% for publication in publications %}

  {{publication.title}}

  {% if publication.id in user_publication_set %}
      i am already interested
  {% endif %}

{% endfor %}

我会这样想：

{% if user.id in publication.users_interested__id %}

{% if request.user in publication.users_interested.all %}

试着这样做：

{% if user.id in publication.users_interested__id %}

{% if request.user in publication.users_interested.all %}

• request.user

  属性保存当前登录的用户
• 然后将

  中的
  运算符用于
  出版物.用户感兴趣的.all（）
  （请注意，模板中的
  .all（）
  上没有括号

试着这样做：

{% if user.id in publication.users_interested__id %}

{% if request.user in publication.users_interested.all %}

• request.user

  属性保存当前登录的用户
• 然后将

  中的
  运算符用于
  出版物.用户感兴趣的.all（）
  （请注意，模板中的
  .all（）
  上没有括号

---

这似乎是一个很好的解决方案：
型号.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

view.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

base.html

{% for publication in publications %}

  {{publication.title}}

  {% if currently logged in User is interested in publication (check users_interested) %}
      i am already interested
  {% endif %}

{% endfor %}

{% for publication in publications %}

  {{publication.title}}

  {% if publication.id in user_publication_set %}
      i am already interested
  {% endif %}

{% endfor %}

---

在
中找到此解决方案这似乎是一个不错的解决方案：
型号.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

view.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

base.html

{% for publication in publications %}

  {{publication.title}}

  {% if currently logged in User is interested in publication (check users_interested) %}
      i am already interested
  {% endif %}

{% endfor %}

{% for publication in publications %}

  {{publication.title}}

  {% if publication.id in user_publication_set %}
      i am already interested
  {% endif %}

{% endfor %}

---

在
中找到此解决方案，您必须在视图中加载所需的信息。模板不是用来生成任何内容的（除了html、ofc）。在您的情况下，可能是某种形式的

prefetch\u related（）

或

annotate（）

。您必须在视图中加载所需的信息。模板不是用来生成任何内容的（但是html，ofc）。在您的情况下，可能是某种形式的

预取相关（）

或

注释（）

。在他的模板中有这个循环，如果他有，比如说，1000份出版物，他的页面会突然用1001个查询压碎数据库。这是可行的——但我真的会有几百份出版物，在他的模板中有这个循环，如果他有，比如说，1000份出版物，他的页面会突然用1001个查询压碎数据库ks--但我会有几百份出版物，这确实是一个更好的解决方案。重点是始终让视图确定应该加载哪些数据，这样它就可以控制逻辑。这正是您所做的。这确实是一个更好的解决方案。重点是始终让视图确定应该加载哪些数据，这样它就可以控制逻辑控制逻辑，你就是这么做的。