如何在Django视图中定义表单的Select字段的选项时使用它们？

huangapple
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英文:

How to use choices of a Select field of a form, when defined in the view in Django?

问题

我有一个与选择输入相关的表单问题。此输入用于从列表中选择用户。该列表应仅包含当前使用的组中的用户。

我找到了一个解决方案，但我对表单定义中的def __init__部分的工作原理并不完全了解（我不完全理解这部分的工作方式）。当然，我的代码没有起作用：我得到了正确的表单，并且我需要的选项，但是如果提交数据，它不会保存在数据库中。

我已经能够检查表单是否有效（它无效），错误如下：

类别 - 请选择一个有效的选项。该选择不是可用选项之一。

（对于用户字段，我有相同的错误）。我在这方面无法找到方法，所以如果你能帮忙的话，将不胜感激！

我的模型：

  1. class Group(models.Model):
  2.     name = models.CharField(max_length=100)
  3.     def __str__(self):
  4.         return self.name   
  6. class User(AbstractUser):
  7.     groups = models.ManyToManyField(Group)
  8.     current_group = models.ForeignKey(Group, on_delete=models.SET_NULL,blank=True,null=True,related_name="current_group")
  10. class Category(models.Model):
  11.     name = models.CharField(max_length=100)
  12.     groups = models.ManyToManyField(Group)
  14.     def __str__(self):
  15.         return self.name
  17. class Expenses(models.Model):
  18.     date = models.DateTimeField()
  19.     amount = models.DecimalField(decimal_places=2, max_digits=12)
  20.     category = models.ForeignKey(Category, on_delete=models.CASCADE)
  21.     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
  22.     group = models.ForeignKey(Group, on_delete=models.CASCADE)
  23.     comment = models.CharField(max_length=500)
  25.     def __str__(self):
  26.         return self.amount

我的表单：

  1. class CreateExpenseForm(forms.ModelForm):
  2.     class Meta:
  3.         model = Expenses
  4.         fields = ['date', 'amount', 'category', 'user','comment']
  5.         widgets={'date':DateInput(attrs={'placeholder':'Date', 'class':'form-input', 'type':'date'}),
  6.                  'amount':TextInput(attrs={'placeholder':'Amount', 'class':'form-input', 'type':'text'}),
  7.                  'category':Select(attrs={'placeholder':'Category', 'class':'form-select', 'type':'text'}),
  8.                  'user':Select(attrs={'placeholder':'User', 'class':'form-select', 'type':'text'}),
  9.                  'comment':TextInput(attrs={'placeholder':'Comment', 'class':'form-input', 'type':'text'}),}
  10.     
  11.     def __init__(self, *args, **kwargs):
  12.         user_choices = kwargs.pop('user_choices', None)
  13.         category_choices = kwargs.pop('category_choices', None)
  14.         
  15.         super().__init__(*args, **kwargs)
  16.         if user_choices:
  17.             self.fields['user'].choices = user_choices
  18.         if category_choices:
  19.             self.fields['category'].choices = category_choices

我的视图：

  1. def SummaryView(request):
  2.     createExpenseForm = CreateExpenseForm(user_choices=[(user.username, user.username) for user in request.user.current_group.user_set.all()],
  3.                                           category_choices=[(category.name, category.name) for category in request.user.current_group.category_set.all()])
  4.     if request.method == "POST":
  5.         if 'createExpense' in request.POST:
  6.             createExpenseForm = CreateExpenseForm(user_choices=[(user.username, user.username) for user in request.user.current_group.user_set.all()],
  7.                                                   category_choices=[(category.name, category.name) for category in request.user.current_group.category_set.all()],
  8.                                                   data=request.POST)
  9.             if createExpenseForm.is_valid():
  10.                 expense = createExpenseForm.save(commit=False)
  11.                 expense.group = request.user.current_group
  12.                 expense.save()
  13.             else:
  14.                 messages.success(request, "Error!")
  15.     
  16.     context = {'createExpenseForm':createExpenseForm}
  17.     return render(request, 'app/summary.html', context)

希望这对你有所帮助！

英文:

I have an issue with a form with a Select input. This input is used to select a user in a list. The list should only contain user from the group currently used.

I found a solution, however I am not completely sure of what am I doing in the form definition (I do not fully understand how works the def __init__ part). And of course, my code is not working : I obtain the right form, with the choices I need, however if a submit data, it's not saved in the database.

I have been able to check if the form is valid (it is not), the error is the following :

> Category - Select a valid choice. That choice is not one of the available choices.

(I have the same error for the user field). I can't find my way in this, so if you can help, would be very appreciated!

My models:

  1. class Group(models.Model):
  2.     name = models.CharField(max_length=100)
  3.     def __str__(self):
  4.         return self.name   
  5.     
  6. class User(AbstractUser):
  7.     groups = models.ManyToManyField(Group)
  8.     current_group = models.ForeignKey(Group, on_delete=models.SET_NULL,blank = True , null = True, related_name="current_group")
  10. class Category(models.Model):
  11.     name = models.CharField(max_length=100)
  12.     groups = models.ManyToManyField(Group)
  14.     def __str__(self):
  15.         return self.name
  17. class Expanses(models.Model):
  18.     date = models.DateTimeField()
  19.     amount = models.DecimalField(decimal_places=2, max_digits=12)
  20.     category = models.ForeignKey(Category, on_delete=models.CASCADE)
  21.     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
  22.     group = models.ForeignKey(Group, on_delete=models.CASCADE)
  23.     comment = models.CharField(max_length=500)
  24.     
  25.     def __str__(self):
  26.         return self.amount

My form:

  1. class CreateExpanseForm(forms.ModelForm):
  2.     class Meta:
  3.         model = Expanses
  4.         fields = ['date', 'amount', 'category', 'user','comment']
  5.         widgets={'date':DateInput(attrs={'placeholder':'Date', 'class':'form-input', 'type':'date'}),
  6.                  'amount':TextInput(attrs={'placeholder':'Amount', 'class':'form-input', 'type':'text'}),
  7.                  'category':Select(attrs={'placeholder':'Category', 'class':'form-select', 'type':'text'}),
  8.                  'user':Select(attrs={'placeholder':'user', 'class':'form-select', 'type':'text'}),
  9.                  'comment':TextInput(attrs={'placeholder':'comment', 'class':'form-input', 'type':'text'}),}
  10.     
  11.     def __init__(self, *args, **kwargs):
  12.         user_choices = kwargs.pop('user_choices', None)
  13.         category_choices = kwargs.pop('category_choices', None)
  14.         
  15.         super().__init__(*args, **kwargs)
  16.         if user_choices:
  17.             self.fields['user'].choices = user_choices
  18.         if category_choices:
  19.             self.fields['category'].choices = category_choices

My view:

  1. def SummaryView(request):
  2.     createExpanseForm = CreateExpanseForm(user_choices = [(user.username, user.username) for user in request.user.current_group.user_set.all()],
  3.                                           category_choices = [(category.name, category.name) for category in request.user.current_group.category_set.all()])
  4.     if request.method == "POST":
  5.         if 'createExpanse' in request.POST:
  6.             createExpanseForm = CreateExpanseForm(user_choices = [(user.username, user.username) for user in request.user.current_group.user_set.all()],
  7.                                                   category_choices = [(category.name, category.name) for category in request.user.current_group.category_set.all()],
  8.                                                   data=request.POST)
  9.             if createExpanseForm.is_valid():
  10.                 expanse = createExpanseForm.save()
  11.                 if expanse is not None:
  12.                     expanse.group = request.user.current_group
  13.                     expanse.save()
  14.                 else:
  15.                     messages.success(request, "Error!")
  16.             
  17.     context = {'createExpanseForm':createExpanseForm}
  18.     return render(request, 'app/summary.html', context)

答案1

得分: 1

The form field of a ForeignKey is a ModelChoiceField, this needs the primary key of the item to work with, not the name of a category. You thus try to do too much yourself, and thus invalidated the data of the form field.

I suggest that you let the form handle it and specify the queryset when necessary:

  1. class CreateExpanseForm(forms.ModelForm):
  2.     def __init__(self, *args, user=None, **kwargs):
  3.         super().__init__(*args, **kwargs)
  4.         if user is not None:
  5.             self.fields['user'].queryset = user.current_group.user_set.all()
  6.             self.fields['category'].queryset = user.current_group.category_set.all()
  8.     class Meta:
  9.         model = Expanses
  10.         fields = ['date', 'amount', 'category', 'user', 'comment']
  11.         widgets = {
  12.             'date': DateInput(
  13.                 attrs={
  14.                     'placeholder': 'Date',
  15.                     'class': 'form-input',
  16.                     'type': 'date',
  17.                 }
  18.             ),
  19.             'amount': TextInput(
  20.                 attrs={
  21.                     'placeholder': 'Amount',
  22.                     'class': 'form-input',
  23.                     'type': 'text',
  24.                 }
  25.             ),
  26.             'category': Select(
  27.                 attrs={
  28.                     'placeholder': 'Category',
  29.                     'class': 'form-select',
  30.                     'type': 'text',
  31.                 }
  32.             ),
  33.             'user': Select(
  34.                 attrs={
  35.                     'placeholder': 'user',
  36.                     'class': 'form-select',
  37.                     'type': 'text',
  38.                 }
  39.             ),
  40.             'comment': TextInput(
  41.                 attrs={
  42.                     'placeholder': 'comment',
  43.                     'class': 'form-input',
  44.                     'type': 'text',
  45.                 }
  46.             ),
  47.         }

In the view you can then just pass the logged in user:

  1. from django.contrib.auth.decorators import login_required
  2. from django.shortcuts import redirect
  4. @login_required
  5. def summary_view(request):
  6.     form = CreateExpanseForm(user=request.user)
  7.     if request.method == 'POST':
  8.         if 'createExpanse' in request.POST:
  9.             form = CreateExpanseForm(
  10.                 request.POST, request.FILES, user=request.user
  11.             )
  12.             if form.is_valid():
  13.                 form.instance.group = request.user.current_group
  14.                 expanse = form.save()
  15.                 return redirect('name-of-some-view')
  17.     context = {'createExpanseForm': form}
  18.     return render(request, 'app/summary.html', context)

Note: Functions are normally written in snake_case, not PascalCase, therefore it is advisable to rename your function to summary_view, not SummaryView.

Note: You can limit views to authenticated users with the @login_required decorator.

Note: In case of a successful POST request, you should make a redirect to implement the Post/Redirect/Get pattern. This avoids that you make the same POST request when the user refreshes the browser.

英文:

The form field of a ForeignKey is a ModelChoiceField&nbsp;<sup>[Django-doc]</sup>, this neecds the primary key of the item to work with, not the name of a category. You thus try to do too much yourself, and thus invalidated the data of the form field.

I suggest that you let the form handle it and specify the queryset when necessary:

<pre><code>class CreateExpanseForm(forms.ModelForm):
def init(self, *args, user=None, **kwargs):
super().init(*args, **kwargs)
if user is not None:
self.fields['user']<b>.queryset</b> = user.current_group.user_set.all()
self.fields[
'category'
]<b>.queryset</b> = user.current_group.category_set.all()

  1. class Meta:
  2.     model = Expanses
  3.     fields = [&#39;date&#39;, &#39;amount&#39;, &#39;category&#39;, &#39;user&#39;, &#39;comment&#39;]
  4.     widgets = {
  5.         &#39;date&#39;: DateInput(
  6.             attrs={
  7.                 &#39;placeholder&#39;: &#39;Date&#39;,
  8.                 &#39;class&#39;: &#39;form-input&#39;,
  9.                 &#39;type&#39;: &#39;date&#39;,
  10.             }
  11.         ),
  12.         &#39;amount&#39;: TextInput(
  13.             attrs={
  14.                 &#39;placeholder&#39;: &#39;Amount&#39;,
  15.                 &#39;class&#39;: &#39;form-input&#39;,
  16.                 &#39;type&#39;: &#39;text&#39;,
  17.             }
  18.         ),
  19.         &#39;category&#39;: Select(
  20.             attrs={
  21.                 &#39;placeholder&#39;: &#39;Category&#39;,
  22.                 &#39;class&#39;: &#39;form-select&#39;,
  23.                 &#39;type&#39;: &#39;text&#39;,
  24.             }
  25.         ),
  26.         &#39;user&#39;: Select(
  27.             attrs={
  28.                 &#39;placeholder&#39;: &#39;user&#39;,
  29.                 &#39;class&#39;: &#39;form-select&#39;,
  30.                 &#39;type&#39;: &#39;text&#39;,
  31.             }
  32.         ),
  33.         &#39;comment&#39;: TextInput(
  34.             attrs={
  35.                 &#39;placeholder&#39;: &#39;comment&#39;,
  36.                 &#39;class&#39;: &#39;form-input&#39;,
  37.                 &#39;type&#39;: &#39;text&#39;,
  38.             }
  39.         ),
  40.     }&lt;/code&gt;&lt;/pre&gt;

In the view you can then just pass the logged in user:

<pre><code>from django.contrib.auth.decorators import login_required
from django.shortcuts import redirect

@login_required
def summary_view(request):
form = CreateExpanseForm(<b>user=request.user</b>)
if request.method == 'POST':
if 'createExpanse' in request.POST:
form = CreateExpanseForm(
request.POST, request.FILES, <b>user=request.user</b>
)
if form.is_valid():
form<b>.instance.group = request.user.current_group</b>
expanse = createExpanseForm.save()
return redirect('<em>name-of-some-view</em>')

  1. context = {&#39;createExpanseForm&#39;: form}
  2. return render(request, &#39;app/summary.html&#39;, context)&lt;/code&gt;&lt;/pre&gt;

> Note: Functions are normally written in snake_case, not PascalCase, therefore it is
> advisable to rename your function to summary_view, not <s>SummaryView</s>.

> Note: You can limit views to a view to authenticated users with the
> @login_required decorator&nbsp;<sup>[Django-doc]</sup>.

> Note: In case of a successful POST request, you should make a redirect
> <sup>[Django-doc]</sup>
> to implement the Post/Redirect/Get pattern&nbsp;<sup>[wiki]</sup>.
> This avoids that you make the same POST request when the user refreshes the
> browser.

huangapple
  • 本文由 发表于 2023年5月22日 01:41:06
  • 转载请务必保留本文链接：https://go.coder-hub.com/76301163.html
  • django
  • forms
  • python
  • selectinput
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