Django: Cannot validate a form without an initial foreignkey value

Question

I have a form in django views.py.

diagnosis.patient is a foreignkey of demographics.patient_id.

my_diagnosis form is not valid because patient is empty. Is there a way to fix this?

def input(request):

    context = RequestContext(request)
    print context
    ret = cache.get('input-rendered')

    if request.method == 'POST':

        my_demographics = DemographicForm(request.POST, prefix="demo")
        my_diagnosis = DiagnosisForm(request.POST, prefix='diag')


        if (my_demographics.is_valid() ):
            print "dem and diag validation"
            my_demographics_object = my_demographics.save(commit=False)
            my_demographics_object.author = request.user
            my_demographics_object.save()
            #my_diagnosis = DiagnosisForm(request.POST, prefix='diag', initial={'patient':my_demographics_object.patient_id} )

            print "my dem id"
            print my_demographics_object.patient_id
        if (my_diagnosis.is_valid()):
            my_diagnosis_object=my_diagnosis.save(commit=False)
            my_diagnosis_object.patient = my_demographics_object.patient_id
            my_diagnosis_object.author = request.user
            my_diagnosis_object.save()

This is my Diagnosis form in forms.py:

class DiagnosisForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):

        super(DiagnosisForm, self).__init__(*args, **kwargs)

        self.fields['diagnosis_circumstances_date']= forms.DateField(label=('Date'),required=False,
        widget=DateTimePicker(options={"format": "YYYY-MM-DD",
                                       "pickTime": False,
                                       "startDate": "1900-01-01"}))


        self.helper=FormHelper(form=self)

        self.fields['icd_10_desc']= forms.ModelChoiceField(queryset=icd_10.objects.all(),
                                    widget=autocomplete_light.ChoiceWidget("icd_10Autocomplete"))
        self.fields['icd_10_desc'].label = "ICD-10 description"
        diagnosis_option_value = (
        ('b-thalassaemia syndromes', 'b-thalassaemia syndromes',),
        ('a-thalassaemia syndromes', 'a-thalassaemia syndromes'),
        ('Sickle cell syndromes', 'Sickle cell syndromes'),
        ('Other haemoglobin variants','Other haemoglobin variants'),
        ('Red cell membrane disorders','Red cell membrane disorders'),
        ('Red cell enzyme disorders','Red cell enzyme disorders'),
        ('Congenital dyserythropoietic anaemias','Congenital dyserythropoietic anaemias')
    )
        self.fields['diagnosis_option']=forms.MultipleChoiceField(choices=diagnosis_option_value, widget=forms.CheckboxSelectMultiple())



        diagnosis_circumstances_value = (
        ('Antenatal diagnosis','Antenatal diagnosis'),
        ('Neonatal diagnosis','Neonatal diagnosis'),
        ('By the presence of affected related','By the presence of affected related'),
        ('Clinical diagnosis', 'Clinical diagnosis'),
        ('Other','Other')

        )
        self.fields['diagnosis_circumstances']=forms.MultipleChoiceField(choices=diagnosis_circumstances_value, widget=forms.CheckboxSelectMultiple())
        #self.fields['patient'].queryset = Demographic.objects.filter(patient_id=self.instance.patient)
        self.helper.field_class = 'col-md-8'
        self.helper.label_class = 'col-md-3'

        #self.helper.form_class = 'forms-horizontal'
        self.helper.layout = Layout(
            Fieldset (
                # 'patient',
                '<b>Diagnosis information</b>',
                Div(
                    #HTML(u'<div class="col-md-2"></div>'),
                    Div('age_of_diagnosis',css_class='col-md-6'),
                    Div('age_at_onset_of_symptoms',css_class="col-md-6"),
                    css_class='row',
                    ),



                'diagnosis_option',
                'record_of_genotype',
                'icd_10_desc',
                'icd_10_code',
                'orpha_code',
                'comment',
                ),


            FormActions(
                Submit('submit', "Save changes"),
                Submit('cancel',"Cancel")
            ),
        )
        self.helper.form_tag = False
        self.helper.form_show_labels = True

    class Meta:
        model = Diagnosis
        exclude = ['patient']
        exclude = ('author',)
        list_display = ('title', 'pub_date', 'author')

This is the result of my_diagnosis.errors:

<ul class="errorlist"><li>patient<ul class="errorlist"><li>This field is required.</li></ul></li></ul>

Answer 1

If you are setting the patient in the view, then just leave the patient form out of the list of fields for you model form:

DiagnosisForm(forms.ModelForm):
    class Meta:
        model = Diagnosis
        fields = ('myfield1', 'myfield2', ...)

You can use exclude if you prefer:

DiagnosisForm(forms.ModelForm):
    class Meta:
        model = Diagnosis
        exclude = ('author', 'patient',)

The problem in your current form is that you have

    exclude = ['patient']
    exclude = ('author',)

The second exclude replaces the first. You should have:

    exclude = ['author', 'patient']

See the model form docs on selecting the fields to use for more info.