Setting value of Django field inside of Form class

Question

I'm trying to set the value of a Django field inside of the Form class. Here is my model

class Workout(models.Model):
    user = models.ForeignKey(User , db_column='userid')

    datesubmitted = models.DateField() 
    workoutdate = models.DateField(); 
    bodyweight = models.FloatField(null=True);
    workoutname = models.CharField(max_length=250)

Here is the form class, in which i am attempting to achieve this:

class WorkoutForm(forms.ModelForm):

    class Meta: 
        model = Workout

    def __init__(self,*args, **kwargs):
        # this is obviously wrong, I don't know what variable to set self.data to
        self.datesubmitted = self.data['datesubmitted']

Ok, sorry guys. I'm passing the request.POST data to the WorkoutForm in my view like this

w = WorkoutForm(request.POST)

However, unfortunately the names of the html elements have different names then the names of the model. For instance, there is no date submitted field in the html. This is effectively a time stamp that is produced and saved in the database.

So I need to be able to save it inside the form class some how, I think.

That is why I am trying to set the datesubmitted field to datetime.datetime.now()

Basically I am using the form class to make the verification easier, and I AM NOT using the form for it's html output, which I completely disregard.

Your form is a ModelForm the how the html elements have different names? — Aamir Rind
– Aamir Rind, Commented Dec 26, 2012 at 0:17

Aamir Rind · Accepted Answer · 2012-12-26 00:32:07Z

3

You have to do that in the save method of your form

class WorkoutForm(forms.ModelForm):

    class Meta: 
        model = Workout

    def __init__(self,*args, **kwargs):
        super(WorkoutForm, self).__init__(*args, **kwargs)

    def save(self, *args, **kw):
        instance = super(WorkoutForm, self).save(commit=False)
        instance.datesubmitted = datetime.now()
        instance.save()

How ever you can set that in your model also to save the current datetime when ever a new object is created:

datesubmitted = models.DateTimeField(auto_now_add=True)

You can set some extra values set in form as:

form = WorkOutForm(curr_datetime = datetime.datetime.now(), request.POST) # passing datetime as a keyword argument

then in form get and set it:

def __init__(self,*args, **kwargs):
    self.curr_datetime = kwargs.pop('curr_datetime')
    super(WorkoutForm, self).__init__(*args, **kwargs)

edited Dec 26, 2012 at 0:32

answered Dec 26, 2012 at 0:09

Aamir Rind

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5 Comments

Lilluda 5 Over a year ago

Now what about for other arbitrary values in arbitrary Forms, I would have to validate all of this data before I call the save method correct? Would I have to completely re-define the is_valid() method to accompany these arbitrary values being assigned to an arbitrary form?

Aamir Rind Over a year ago

the model is going to validate the fields it self. e.g. if you have a field A and it is a required field the form will raise ValidationError if you left it empty

Lilluda 5 Over a year ago

is there any way i can assign that value globally, for instance in the init method? will datesubmitted = self.data['datesubmitted'] do the trick?

Lilluda 5 Over a year ago

Isn't that how you are suppose to access the request.POST data passed to the Form?

Aamir Rind Over a year ago

I have updated the answer check at the end. you should get the data after it is validated using self.cleaned_data

Ignacio Vazquez-Abrams · Accepted Answer · 2012-12-26 00:10:42Z

0

You should not be using a ModelForm for this. Use a normal Form, and either in the view or in a method create a new model instance, copy the values, and return the model instance.

answered Dec 26, 2012 at 0:10

Ignacio Vazquez-Abrams

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2 Comments

Lilluda 5 Over a year ago

Why is this? I'm closely tied with a Model, so then I thought I was suppose to use a ModelForm

Ignacio Vazquez-Abrams Over a year ago

A ModelForm takes the field names from the model. Since this is not what you want, you should not be using one.

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