Question

我正在使用一个考勤系统，该学生可以通过在下拉列表值中查找他们的姓名来标记他们的出勤。然后，学生将按Submit（提交），信息将存储在MarkAtt数据库中。当前它没有显示与班级相应的学生姓名，当我单击“提交”时，它显示以下错误：出现“ valueerror”。 ValueError异常值：无法分配“，，......” MarkAtt.studName“必须是” Namelist“实例。我需要将选定的学生姓名每单击一次存储在数据库中。...< / p>

 class MarkAtt(models.Model):
studName = models.ForeignKey(Namelist,on_delete=models.SET_NULL,blank=True, null=True, default=None)
classGrp = models.ForeignKey('GroupInfo', on_delete=models.SET_NULL, null=True)
currentDate = models.DateField(default=now())
week = models.IntegerField(default=0)
attendance = models.IntegerField(default=1) #1 is present

该模板在一个淹死列表框中显示班级信息，今天的日期和学生的姓名。

   <form method="post" enctype="multipart/form-data">
{% csrf_token %}
Lab Group: {{group.classGrp}} //this is from another view
Day: {{group.day}} 
Time: {{group.time}} 
 Today's date: {{today.date}}
    {{form.as_p}}

视图：

  def mark_stud(request,id):
group = GroupInfo.objects.get(id=id)
studName = Namelist.objects.filter(classGrp=id)
information = {}
information['group'] = group
information['studName'] =studName
if request.method == 'POST':        
    form = studentAttendanceForm(request.POST)
    if form.is_valid():
        att = form.save(commit=False)
        att.studName = information['studName']
        att.currentDate = datetime.datetime.now.date()
        form.save()
        return redirect('namelist.html')
else: 
    form = studentAttendanceForm()



return render(request, 'namelist.html', {'information' :information, 'form':form})

Forms.py

class studentAttendanceForm（forms.ModelForm）：类Meta：型号= MarkAtt 字段= ['studName'] 标签= { '姓名'：'学生姓名' }

def __init__(self,*args, **kwargs):
    super(studentAttendanceForm, self).__init__(*args,**kwargs)
    self.fields['studName'].label = "Select your name:"

但是，表单未显示在模板页面中，并且我无法将值保存在数据库中。非常感谢您的帮助。非常感谢。

Answer 1

您必须在视图中分离GET和POST请求，例如：

if request.method == POST:
    form = studentAttendanceForm(request.POST)
    if form.is_valid():
        att = form.save(commit=False)
        att.studName = information['studName']
        att.currentDate = datetime.datetime.now.date()
        form.save()
        return redirect('namelist.html')
else: # for GET request
    form = studentAttendanceForm()

return render(request, 'namelist.html', {'information' :information, 'form':form})

对于您的表单，最好使用fields而不是exclude：

class studentAttendanceForm(forms.ModelForm):

    class Meta:
        model = MarkAtt 
        fields = ('studName')

    def __init__(self, *args, **kwargs):
        super(studentAttendanceForm, self).__init__(*args, **kwargs)
        self.fields['studName'].label = "Select your name:"

然后在您的模板中
如果您使用form.as_p，则不必调用form.att.label_tag，也不必将其放在<p>标签内
查看文档：{{3}}

<form method="post" enctype="multipart/form-data">
{% csrf_token %}
...
{{form.as_p}}
...

另一个问题是，模板中的group和today是什么？

Lab Group: {{group.classGrp}} 
Day: {{group.day}} 
Time: {{group.time}} 
Today's date: {{today.date}}

您的视图中未包含group和today，因此不应打印任何内容。
因为在渲染功能中，您仅发送information和form，
没有group和today
return render(request, 'namelist.html', {'information' :information, 'form':form})
为了增加可读性代码，最好这样写：

context = {
    'information': information,
    'form': form,
    'group': ......, # fill this
    'today': ...... # fill this too
}
return render(request, 'namelist.html', context)

编辑

要基于组ID指定下拉列表，您可以传递组对象并以.queryset格式使用__init__

group = GroupInfo.objects.get(id=id)
if request.method == 'POST':
    form = studentAttendanceForm(request.POST, class_group=group)
    ...
else:
    form = studentAttendanceForm(request.POST, class_group=group)

def __init__(self,*args, **kwargs):
    class_group = kwargs.pop('class_group')
    super(studentAttendanceForm, self).__init__(*args,**kwargs)
    self.fields['studName'].label = "Select your name:" 
    self.fields['studName'].queryset = Namelist.objects.filter(classGrp=class_group)

Answer 2

我认为您的表单不会显示，因为它仅在“ try andexcept”部分内定义。尝试使用如下代码：

def mark_stud(request, class_id,id):
    form = studentAttendanceForm(request.POST)
    if (not class_id or not id):
        return HttpResponseForbidden()

    else:
        try:
            classGrp = None
            information = {}
            information['studName'] = Namelist.objects.get(name=id)


            if form.is_valid():
                att = form.save(commit=False)
                att.studName = information['studName']
                att.currentDate = datetime.datetime.now.date()
                form.save()
                return redirect('namelist.html')

        except ObjectsDoesNotExist:
            print("no entries")
            return redirect('namelist.html')        

    return render(request, 'namelist.html', {'information' :information, 'form':form})

如何将下拉列表值保存到Django数据库中

2 个答案: