无法将检索到的表单数据应用于多个对象

Question

我正在尝试使用具有一个字段的表单（在呈现的template.html 中显示为下拉列表）来更改同一模型的多个对象的属性。但是，由于某种原因，我无法将检索到的表单数据应用于对象。

models.py:

class Player(models.Model):
    class Race(models.TextChoices):
        HUMAN = "Human"
        UNDEAD = "Undead"
    race = models.CharField(choices=Race.choices)

forms.py:

class PlayerRaceForm(ModelForm):
    class Meta:
        model = Player
        fields = [
            'race'
        ]

views.py:

def index(request):
    players = Player.objects.all()
    player_race_form = PlayerRaceForm()
    if request.method == 'POST':
        print(player_race_form.errors) # nothing here
        print(player_race_form.non_field_errors) # see next code block
        if player_race_form.is_valid(): # it aint for some reason :/
            for player in players:
                player.race = player_race_form.cleaned_data['race']
                player.save()
    
    context = {'player_race_form': player_race_form,}
    return render(request, 'template.html', context)

开启print(player_race_form.non_field_errors):

<bound method BaseForm.non_field_errors of <PlayerRaceForm bound=False, valid=False, fields=(race)>>

我尝试bypass is_valid 和 cleaned_data 并使其以某种方式工作，但它保存了一个明显错误的值，不在 Race 类中。

def index(request):
    players = Player.objects.all()
    player_race_form = PlayerRaceForm()
    if request.method == 'POST':
        print(player_race_form.errors) # nothing here
        print(player_race_form.non_field_errors) # see next code block
        for player in players:
            player.race = player_race_form['race'].value()
            # player.race = player_race_form.data['race'] #MultiValueDictKeyError
            player.save()

    context = {'player_race_form': player_race_form,}
    return render(request, 'template.html', context)

还尝试只修改一个对象：

def index(request):
    players = Player.objects.all()
    player_race_form = PlayerRaceForm()
    if request.method == 'POST':
        print(player_race_form.errors) # nothing here
        print(player_race_form.non_field_errors) # see next code block
        if player_race_form.is_valid(): # it aint for some reason :/
           player[0].race = player_race_form.cleaned_data['race']
           player[0].save()
    
    context = {'player_race_form': player_race_form,}
    return render(request, 'template.html', context)

还是不行。

虽然理论上很容易通过创建一些 if-else 语句来将表单中的值与Race 中的实际值相匹配来破解它，但这样做有点浪费，所以我'想要一个 Django 方法来解决这个问题。

Answer 1

我已经重现了您的错误。然后使用来自 GeeksForGeeks 的关于 forms 的建议 我在几个地方更改了您的代码：

models.py：

class Player(models.Model):
    class Race(models.TextChoices):
        HUMAN = "Human"
        UNDEAD = "Undead"
    race = models.CharField(max_length=6, choices=Race.choices)  # added max_lenght because of makemigrations error

forms.py：

from django import forms  # imported it and used it below 
from projects.models import Player


class PlayerRaceForm(forms.ModelForm):  # instead of ModelForm
    class Meta:
        model = Player
        fields = "__all__"  # geeks suggestion, but yours work just fine

views.py：

def index(request):
    context = {}
    player_race_form = PlayerRaceForm(request.POST or None, request.FILES or None)
    if player_race_form.is_valid():
        player_race_form.save()
        # print(player_race_form)  # uncomment ii to see valid, saved form

    context['form'] = player_race_form
    return render(request, 'projects/template.html', context)

我的 templates.html 也是这样的：

<form action = "" method = "post">
    {% csrf_token %}
    {{form}}
    <input type="submit" value="Submit">
</form>

和我在控制台中的输出：

<tr><th><label for="id_race">Race:</label></th><td><select name="race" required id="id_race">
  <option value="">---------</option>

  <option value="Human" selected>Human</option>

  <option value="Undead">Undead</option>

</select></td></tr>

我认为，它正确保存了选定的值:)