Django:表单成功，但未上载图像

Question

型号.PY

class Campaign(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    campaign_image = models.ImageField(default="profilepic.jpg",upload_to="campaign_pictures")

FORMS.PY

class RaiseFundsFrom3(forms.ModelForm):
    class Meta:
        model = Campaign
        fields = ['campaign_image']

视图.PY

@login_required
def raise_funds_medical_3(request):
    if request.method == 'POST':
        form = RaiseFundsFrom3(request.POST, request.FILES or None, instance=request.user)
        if form.is_valid():
            check = form.save(commit=False)
            check.save()
            return HttpResponse('form worked')
    else:
        form = RaiseFundsFrom3()
        return render(request,'funds/raise_funds_medical_3.html',{'form':form})

url.PY

path('raise/medical/photo', views.raise_funds_medical_3, name="raise_funds_medical_3"),

筹集资金\u医疗\u 3.html

<form method="post" enctype="multipart/form-data">
  {% csrf_token %}
  <div class="form-group pt-2">
    <small>Photo formats must be PNG / JPG / JPEG</small>
    <input type="file" name="campaign_image" />
  </div>
  <button class="btn btn-lg button_bfg_blue" type="submit"> <small><b> NEXT  </b></small> </button>
</form>

在表单提交时，我没有收到任何错误，但图像没有上传到所需的文件夹。 但是，在views.py中的raise_funds_medical_3函数中，如果我删除instance=request.user，则会上载图像，但会出现以下错误：非空约束失败：funds_campaign.user_id

Answer 1

您的表单是Campaign的ModelForm，因此它的instance必须是Campaign。不要将request.user指定为它的instance

现在，您的表单没有包含保存user所需的Campaign字段，因此在保存到数据库之前，您应该在视图中自己分配该字段：

campaign = form.save(commit=False)  # this gives your the form's instance
campaign.user = request.user  # this assigns the user
campaign.save()  # this commits to the database

您还应该处理表单无效的情况。这非常简单，只需取消缩进视图函数中的最后一个return，以便在form无效的情况下也调用return render(...)

最后，最好的做法是重定向到另一个视图，而不是在表单有效时返回响应。这样，当用户刷新页面时，表单不会再次提交。您的最终代码应该如下所示：

@login_required
def raise_funds_medical_3(request):
    if request.method == 'POST':
        form = RaiseFundsFrom3(request.POST, request.FILES or None)
        if form.is_valid():
            check = form.save(commit=False)
            check.user = request.user
            check.save()
            return redirect(<url_pattern>)
    else:
        form = RaiseFundsFrom3()
    return render(request,'funds/raise_funds_medical_3.html',{'form':form})