擅长:python、mysql、java
<p>首先,安排你的观点是不好的,虽然它会工作。已验证的表单数据将在<code>form.cleaned_data</code>字典中。这些数据已经被很好地转换为Python类型。IntegerField、DecimalField和FloatField等字段将值分别转换为Python int、Decimal和float。在</p>
<pre><code>from yourapp.model import Daten
def dateneingabe(request):
if request.method == "POST":
form = DatenForm(request.POST)
if form.is_valid():
instance = form.save(commit=False)
Stand_db = Daten.objects.lastest(Verbraucher)
#you used Stand instead of instance.stand and since instance.stand is decimalfield is will be processed nicely
instance.Verbrauch = do_calc(instance.Stand - float(Stand_db))
instance.save()
return HttpResponseRedirect('/')
else:
form = DatenForm()
return render(request, 'verbrauch/eingabe.html', {'form': form})
</code></pre>
<p>我希望它能帮上忙</p>