的Django無法分配 「X'」： 「Y」 必須是一個「z.`

Question

我收到以下錯誤：

Internal Server Error: /change_chosenCharity/ 

ValueError at /change_chosenCharity/ 
Cannot assign "19L": "Profile.chosenCharity" must be a "Charity" instance. 

從以下觀點：

@login_required 
def change_chosenCharity(request): 
    if request.method == 'POST': 
     form = updateCharity(request.POST) 
     if form.is_valid(): 
      currentUser = request.user 
      currentUserID = currentUser.id 
      chosenCharityQuery = Charity.objects.filter(id=request.POST['currentCharities']) 
      charity_id = chosenCharityQuery[0].id 
      created = Profile.objects.update_or_create(
       user_id=currentUserID, 
       defaults={'chosenCharity': charity_id}, 
      ) 
      messages.success(request, 'Your chosen charity has been updated.') 
      return redirect(reverse('profile')) 
    else: 
     form = updateCharity() 
    return render(request, 'meta/changechosencharity.html', {'form': form}) 

的結果後從Django中顯示：

POST: 
currentCharities = u'19' 

19絕對是慈善事業的一個實例我有這個問題之前，總是解決它比較快...我已經尋找。在這裏，但無法找到解決我的問題。任何幫助，將不勝感激。

附加信息：

HTML表單：

<form class="form-horizontal" role="form" method="post" action=""> 
    {% csrf_token %} 
    <fieldset> 
     <div class="form-group"> 
     <label class="col-sm-4 control-label">{{ form.currentCharities.label }}:</label> 
     <div class="col-sm-8"> 
      {{ form.currentCharities }} 
      <div class="text-danger"> 
      {% for error in form.currentCharities.errors %}{{ error }}<br/>{% endfor %} 
      </div> 
     </div> 
     </div> 
     <div class="form-group"> 
     <div class="text-right col-sm-12"> 
      <button type="submit" class="btn btn-primary">Change Charity</button> 
     </div> 
     </div> 
    </fieldset> 
    </form> 

的Django模型：

class Charity(models.Model): 
    name = models.CharField(max_length=50, unique=True) 
    website = models.URLField() 
    enabled = models.BooleanField(default=True) 

    def __unicode__(self): 
     return self.name 

    class Meta: 
     ordering = ['name'] 
     verbose_name_plural = 'charities' 

FORM：

class updateCharity(BootstrapForm): 

    currentCharities = forms.ModelChoiceField(queryset=Charity.objects.filter(enabled=1), empty_label=None,widget=forms.Select(attrs={"class": "select-format"})) 
    currentCharities.label = "Charity Options" 


    def clean(self): 
     cleaned_data = self.cleaned_data # individual field's clean methods have already been called 
     return cleaned_data 

Answer 1

您可以通過電子郵件ither更新相關的對象實例：

charity = chosenCharityQuery[0] 
created = Profile.objects.update_or_create(
      user_id=currentUserID, 
      defaults={'chosenCharity': charity}, 
     ) 

或更新相關領域的ID：

charity_id = chosenCharityQuery[0].id 
created = Profile.objects.update_or_create(
      user_id=currentUserID, 
      defaults={'chosenCharity_id': charity_id}, 
     )