Use base_form_class in InlinePanel.

Currently, there is no possible way to specify a form for an inline. For consistency, it should be possible to specify base_form_class in any Model, just like we can do it with Page.

In my case, this is blocking since I would like to use a form field that is not a database field, then parse its data and dispatch it into multiple database fields.

[regmeg]

I’ve dug into the wagtail source code and I think I found the way of how to access the form controls for the orderable (this might work for other types of inline elements/haven’t tested those).

Let’s say you have a model for a page,

class TestPage(Page):

    testPageTitle = RichTextField(blank=True, max_length=250)

    content_panels = Page.content_panels + [
	FieldPanel('testPageTitle'),
	InlinePanel('test_page_field')
    ]

    base_form_class = TestPageForm

with some orderable model, that is linked to the page through a related name ‘test_page_field’,

class TestPageField(Orderable):
    page = ParentalKey(TestPage, on_delete=models.CASCADE, related_name='test_page_field')

    testPageFieldTitle = models.CharField(blank=True, max_length=250)

    panels = [
	FieldPanel('testPageFieldFieldTitle')
    ]

then you can access that within the clean method of the page, via self.formsets['test_page_field'].forms, which is a list of Django form objects, where the regular checks can be done and .add_error() method can be used. The relevant base_form_class would look as follows:

class TestPageForm(WagtailAdminPageForm):

    def clean(self):
	cleaned_data = super().clean()

	#loop over linked orderables
	for form in self.formsets['test_page_field'].forms:

	    #check first if form is valid, otherwise cleaned_data will not be accesible/set
	    if form.is_valid():
	        cleaned_form_data = form.clean()
	        testPageFieldFieldTitle = cleaned_form_data.get('testPageFieldFieldTitle')

	        #execute some validation condition, and raise the error if it fails
	        if testPageFieldFieldTitle is None:
	            form.add_error('testPageFieldFieldTitle', 'please dont leave me empty')

	return cleaned_data

I hope this helps.

[engAmirEng]

I think I find the solution:

class SomeOrderable(Orderable):
    panels = [
        SnippetChooserPanel("some_snippet"),
        FieldPanel("my_field_thst_is_not_in_model"),
    ]
    page = ParentalKey(
        "SomePage",
        related_name="page_someorderable",
        on_delete=models.CASCADE,
    )
    some_snippet= models.ForeignKey(
        "SomModel", on_delete=models.CASCADE
    )
class MyWagtailAdminModelForm(WagtailAdminModelForm):
    my_field_thst_is_not_in_model = forms.IntegerField(widget=forms.Select(choices=((1, "one"), (2, "two"))))

class MyInlinePanel(InlinePanel):
    def __init__(self, relation_name, form=None, *args, **kwargs):
        self.form = form
        super(MyInlinePanel, self).__init__(relation_name, *args, **kwargs)
    def clone_kwargs(self):
        kwargs = super().clone_kwargs()
        kwargs.update(form=self.form)
        return kwargs
    def get_form_options(self):
        form_options = super(MyInlinePanel, self).get_form_options()
        form_options['formsets'][self.relation_name].update(form=self.form)
        return form_options

class SomePage(Page):
    content_panels = Page.content_panels + [
        MyInlinePanel("page_someorderable", form=MyWagtailAdminModelForm),
    ]

1-you define your custom form for the orderable that as you know it should subclass the WagtailAdminModelForm 2-subclass the InlinePanel as it’s shown in the pic I try this works on wagtail 3

A bigger question, is there any particular reason that it is not a part of wagtail support? maybe some issues and bugs?