我正在使用 Django 中的 ModelForm 为数据库中的模型构建一个编辑表单。表单中的每个字段都是可选的，因为用户可能只想编辑一个字段。
我遇到的问题是，当我在 View 中调用 save() 时，任何空字段都将保存在实例的原始值上(例如，如果我只输入新的 first_name ，last_name 和 ecf_code 字段将在相应实例中保存一个空字符串。)
形式:
class EditPlayerForm(forms.ModelForm):
class Meta:
model = Player
fields = ['first_name', 'last_name', 'ecf_code']
def __init__(self, *args, **kwargs):
super(EditPlayerForm, self).__init__(*args, **kwargs)
self.fields['first_name'].required = False
self.fields['last_name'].required = False
self.fields['ecf_code'].required = False
View :
def view(request, player_pk = ''):
edit_player_form = forms.EditPlayerForm(auto_id="edit_%s")
if "edit_player_form" in request.POST:
if not player_pk:
messages.error(request, "No player pk given.")
else:
try:
selected_player = Player.objects.get(pk = player_pk)
except Player.DoesNotExist:
messages.error(request, "The selected player could not be found in the database.")
return redirect("players:management")
else:
edit_player_form = forms.EditPlayerForm(
request.POST,
instance = selected_player
)
if edit_player_form.is_valid():
player = edit_player_form.save()
messages.success(request, "The changes were made successfully.")
return redirect("players:management")
else:
form_errors.convert_form_errors_to_messages(edit_player_form, request)
return render(
request,
"players/playerManagement.html",
{
"edit_player_form": edit_player_form,
"players": Player.objects.all(),
}
)
我尝试重写表单的 save() 方法来显式检查哪些字段在 POST 请求中具有值，但这似乎没有产生任何影响也有区别。
尝试重写保存方法:
def save(self, commit = True):
# Tried this way to get instance as well
# instance = super(EditPlayerForm, self).save(commit = False)
self.cleaned_data = dict([ (k,v) for k,v in self.cleaned_data.items() if v != "" ])
try:
self.instance.first_name = self.cleaned_data["first_name"]
except KeyError:
pass
try:
self.instance.last_name = self.cleaned_data["last_name"]
except KeyError:
pass
try:
self.instance.ecf_code = self.cleaned_data["ecf_code"]
except KeyError:
pass
if commit:
self.instance.save()
return self.instance
我也没有 Player 模型的任何默认值，因为文档说 ModeForm 将使用这些默认值作为表单提交中缺少的值。
编辑:
这是整个EditPlayerForm:
class EditPlayerForm(forms.ModelForm):
class Meta:
model = Player
fields = ['first_name', 'last_name', 'ecf_code']
def __init__(self, *args, **kwargs):
super(EditPlayerForm, self).__init__(*args, **kwargs)
self.fields['first_name'].required = False
self.fields['last_name'].required = False
self.fields['ecf_code'].required = False
def save(self, commit = True):
# If I print instance variables here they've already
# been updated with the form values
self.cleaned_data = [ k for k,v in self.cleaned_data.items() if v ]
self.instance.save(update_fields = self.cleaned_data)
if commit:
self.instance.save()
return self.instance
编辑:
好的，这就是解决方案，我想我应该把它放在这里，因为它可能对其他人有用(我当然从中学到了一些东西)。
事实证明，模型表单的 is_valid() 方法实际上对您传递到表单中的实例进行了更改，为 save() 做好了准备方法来保存它们。因此，为了解决这个问题，我扩展了表单的 clean() 方法:
def clean(self):
if not self.cleaned_data.get("first_name"):
self.cleaned_data["first_name"] = self.instance.first_name
if not self.cleaned_data.get("last_name"):
self.cleaned_data["last_name"] = self.instance.last_name
if not self.cleaned_data.get("ecf_code"):
self.cleaned_data["ecf_code"] = self.instance.ecf_code
这基本上只是检查字段是否为空，如果字段为空，则用给定实例中的现有值填充它。 clean() 在使用新表单值设置实例变量之前被调用，因此这样，任何空字段实际上都会填充相应的现有实例数据。
最佳答案
您也许可以使用 update() 方法而不是 save()
或参数 update_field
self.instance.save(update_fields=['fields_to_update'])
仅使用非空值构建列表['fields_to_update']。
它甚至应该与您尝试过的理解一起工作:
self.cleaned_data = [ k for k,v in self.cleaned_data.items() if v ]
self.instance.save(update_fields=self.cleaned_data)
编辑:
不重写保存方法(并在表单中注释掉此尝试):
not_empty_data = [ k for k,v in edit_player_form.cleaned_data.items() if v ]
print(not_empty_data)
player = edit_player_form.save(update_fields=not_empty_data)
关于python - ModelForm 保存带有空字段的模型数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45772137/