Passing data to max_value via the function. How?

Using Django Forms & APIs
1

Hello!!!

I want max_value to be checked in the form after entering, not through a static value, but through a function, in this case check_balance()

forms.py

class WwmoneyForm(forms.Form):
    amount = forms.FloatField(min_value=1, max_value=check_balance(), label = "Amount")

models.py

def check_balance(request):
    
    name = request.user.username
    all_users = All_users.objects.all()
    
    for i in all_users:
        if i.nick == name:
           balance = i.balance
          
            
    return balance

when executed , it outputs the following:

TypeError: check_balance() missing 1 required positional argument: ‘request’

2

You have a couple things wrong here:

Your function definition:

def check_balance(request):
                  ^^^^^^^

Your usage in the form:

max_value=check_balance()
                       ^^

Your form doesn’t normally get the request passed to it, so it can’t pass the request to the check_balance method.

(We’d need to see the view and the model to be able to provide more detailed information about what the appropriate resolution would be.)

Second item:

It is an extremely bad idea to try and use a FloatField for any type of monetary value. You want to use a Decimal field for that purpose. See my comment at Calculating Cost of Items for Finance - #2 by KenWhitesell and the posts and links that it references.

Third, do yourself a favor and change your check_balance function to perform a query rather than iterating over all users to find a match. (Also, what is the All_users model?)

1 Like
3

THANK YOU!

views.py

I did not prescribe anything for their functions in “view”, I thought that it was not necessary

models.py

class Wwmoney(models.Model):
    nick = models.CharField('Nick', max_length=50)
    amount = models.FloatField()

:handshake:

class All_users(models.Model):
    nick = models.CharField('Nick', max_length=50)
    account = models.CharField('Acc', max_length=50)
    email = models.EmailField("Email", max_length=50)
    balance = models.FloatField()
4

A form doesn’t initiate any activity by itself. Forms are used by views to process data being submitted from a browser.

5

yes, you are right

def wwmoney(request): 
    
    # if this is a POST request we need to process the form data
    if request.method == 'POST':
        # create a form instance and populate it with data from the request:
        form = WwmoneyForm(request.POST) # A form bound to the POST data
       
        if form.is_valid():
            
            name = request.user.username
            
            cd = form.cleaned_data
            pc = Wwmoney(amount = cd['amount'], datetime_addmoney = dtime(), method = "1", nick = name)
            all_users = All_users.objects.all()
            
            for i in all_users:
                if i.nick == name:
                    bal = i.balance
                    balance1 = i.balance - cd['amount']
                    balance1 = All_users(id = i.id, nick = i.nick, account = i.account, email = i.email, balance = balance1)
                else:
                    pass
            balance1.save() 
            pc.save()
                        
                       
            return HttpResponseRedirect('/list_users')

    # if a GET (or any other method) we'll create a blank form
    else:
        form = WwmoneyForm()
   
    all_users = All_users.objects.all()
    
    name1 = request.user.username
    for k in all_users:
        if k.nick == name1:
           bal = k.balance

    return render(request, 'money/wwmoney.html', {'form': form, "all_users": all_users, "bal":bal})
6

Just out of curiousity, have you worked your way through either the Official Django Tutorial or the Django Girls Tutorial? There are a number of fundamental mistakes in the code here with both the view and the handling of data in the form.

If you haven’t worked your way through those tutorials, I suggest you do so before trying to move forward from here.

If you have, then I suggest you go back and review the work you had done with an eye toward understanding how those views, forms, and queries are constructed.

1 Like