I have a program that uploads a csv of data in order to map values in the csv to other values. In order to do this, the user must select which columns in the csv they need to create the mapping, so that no extraneous information is on the mapping page.

To do this I created a dynamic Django by overriding the init function in my ModelForm. The problem is that even though I'm able to dynamically show the column values, when the user tries to select the values and save them to the model, it fails, because the Model choices don't align with the dynamic checkbox values. So I've overridden the Model's init function to populate the model's choices. My problem is I'm not sure how to instantiate the model in the ModelForm to call the init function.

model

class ColumnMapping(models.Model):
    CHOICES =[('row_1', 'A'), ('row_2', 'B'), ('row_3', 'C')]
    company = models.ForeignKey(RawData, on_delete=models.CASCADE)
    columnNames = MultiSelectField(max_length=100, choices=CHOICES)
    
    def __init__(self, *args, **kwargs):
        self.choices = kwargs.pop('choices')
        super(ColumnMapping, self).__init__(*args, **kwargs)
        self._meta.get_field.choices = self.choices

form - I think something needs to happen here in the Meta class, but since the model = ColumnMapping line doesn't instantiate the model (I don't think), I don't think I can pass variables to it.

class ColumnMappingForm(ModelForm):

    def __init__(self, *args, **kwargs):
        self.choices = kwargs.pop('choices')
        super(ColumnMappingForm, self).__init__(*args, **kwargs)
        self.fields['columnNames'].widget.attrs.update({'class': 'form-check'})
        self.fields['columnNames'].choices = self.choices

    class Meta:
        model = ColumnMapping
        fields = ('columnNames',)

views

def columnSelection(request, companyName):
    companyData = RawData.objects.get(companyName = companyName)
    columnNames = list(RawData.objects.get_columnNames(companyData.file.name))
    columnNamesTuple = ()
    for columnName in columnNames:
        tup = (columnName, columnName)
        columnNamesTuple = list(columnNamesTuple)
        columnNamesTuple.append(tup)
        columnNamesTuple = tuple(columnNamesTuple)
    if request.method == "POST":
        form = ColumnMappingForm(request.POST, choices=columnNamesTuple)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse("mappingApp:productMapping", kwargs={'companyName': companyData.companyName}))
        else:
            error = list(form.errors.values())[0]
            return render(request, "mappingApp/columnSelection.html", {
                "form": form,
                "columnNames": columnNames,
                "company": companyData,
                "error": error
            })
    else:
        form = ColumnMappingForm(choices=columnNamesTuple)

        return render(request, "mappingApp/columnSelection.html", {
            "form": form,
            "columnNames": columnNames,
            "company": companyData
            })