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Something we've actually used before, but in Admin, is inlines. Inlines let us create and edit multiple *related* model instances at once.
Like I've been saying, inline formsets, and formsets in general, aren't necessary something you'll be using all the time. They're a great tool to have in your toolset, though, when you do need them.
How about some docs?
FormWizard (we didn't use this, but I mentioned it so thought you might want to see. It's a way to link several forms together in a row.)
In Django Basics,
we made an inline in the admin
0:00
to make it a little easier to
create steps in our courses.
0:03
We can do something very similar
with our own forms and model forms.
0:06
I'll admit formsets and
0:10
inline formsets aren't something I've
used very often in my own career.
0:12
You may very well have
the same experience, but
0:16
they're a great thing to know about
just in case you do need them.
0:18
And so, with that,
let's jump into workspaces.
0:22
Another way of doing formsets, and
it's a way that we've done in the admin,
0:25
is actually using what's
called an inline formset.
0:30
So I'm gonna scroll up here in the docs.
0:33
And right over here on the side,
it says inline formsets.
0:35
Now inline formsets are different
from regular formsets
0:38
because inline form sets appear in
the model form for another model.
0:44
It's kinda like working in admin
when we had the inlines for
0:50
working with our courses so
that we could add steps to the courses.
0:54
This is the same idea, but it's for
whatever model or form that you want.
0:58
So, let's see about how to.add those.
1:02
I'm gonna do this a little bit backwards,
maybe?
1:05
And I'm actually gonna do it
over here in question_form.
1:08
I'm gonna start on the template first.
1:10
So you remember in answer_form,
1:13
we just printed out formset, like that.
1:16
So we can totally do that
with the model formsets, but
1:21
they don't always look
that great that way.
1:26
So I don't want to do it that way,
[LAUGH] I want to do it in a nicer way.
1:30
So what I'm gonna do, is right here,
after this form.as_p,
1:35
this is where I am gonna
add in the extra bits.
1:38
So first we need to add in
formset.managment_form,
1:41
and this is a special set of fields
that control how many items represented,
1:47
how many forms there are, stuff like that.
1:53
So, this is an important form for
controlling whether or
1:55
not your formset is valid.
1:59
And then,
we're gonna do a bunch of HTML, but
2:02
we're gonna add in our forms individually,
sort of.
2:05
So, role is grid, class is stack and
2:10
hover, style="width: 100%".
2:13
Cool no problem there.
2:19
<thead> <tr> <th
2:22
scope="col" class="text-center"
2:26
style='"width: 10%"
2:34
</th> </tr> </thead>.
2:39
And we're gonna say order, and
then I'm actually gonna copy this row.
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Three, four.
2:53
So this one's gonna be Text.
2:57
And we're gonna take
off all of that stuff.
3:01
And this one is going to be Correct.
3:07
And this one is going to be Delete,
3:10
because we're gonna bring in
the ability to delete answers as well.
3:13
All right, so then <tbody> and
3:18
we need to add in class="order".
3:22
This is for a video or so from now.
3:27
We're gonna add in the ability to
reorder these using drag and drop, but
3:30
let's not worry that for just yet.
3:34
So for form in formset,
cuz formset is a set of forms.
3:36
Logically, right?
3:42
endfor, all right.
3:46
So, then we do a <tr>.
3:48
And we give this a class of answer-form.
3:51
And if form.instance.pk.
3:56
And we'll say item.
3:59
Again this is for our plug in that
we're gonna use in a little bit.
4:02
Actually I need an else in there,
else new.
4:06
All right, cool.
4:12
There's our </tr>.
4:15
And then we need a <td>.
4:18
And we're gonna say form.id,
cuz we want the id to hang around.
4:21
And then form.order and that's gonna print
4:26
out the HTML field for
the order field on the form.
4:31
And then form.text.
4:37
And then <td class="text-center">.
4:41
And then here we're gonna
print out form.correct.
4:49
And then if we have an instance,
we want to offer
4:54
them the ability to delete that instance.
5:00
So, form,
5:05
and then this field is all caps,
which is a little bit strange.
5:10
All right and if, oh no, we need an else.
5:16
But there's nothing in that one.
5:26
And then we close our tr and
we close our endfor.
5:29
And we close our tbody and
our table, okay.
5:32
So that's cool,
that's all of our HTML work.
5:35
And of course I'm gonna have
all this in a download for you.
5:37
It's a decent amount of work there,
isn't it?
5:41
All right, so now,
let's go over here to forms.py.
5:44
So we already have this AnswerFormSet.
5:47
We're gonna add a new one that
is our AnswerInlineFormSet.
5:49
So, AnswerInlineFormSet is
forms.inlineformset_factory.
5:55
And then we specify the model that
the inline is going to appear in.
6:04
So models.question.
6:11
That's the one that we're saving with.
6:12
And then models.answer is the model that
we're going to be editing in our form.
6:16
And I don't want any extra for right now.
6:22
And the fields.
6:26
It's weird that we have to specify fields.
6:28
But we still have to specify fields,
even though we could
6:30
just specify them in a form or something.
6:36
But, nope.
6:38
And then we can tell it
the FormSet that we want to use,
6:40
which is the AnswerFormSet, and that just
handles some of these little tidbits.
6:43
That's not required.
6:49
And min_num=1, we have to have at least 1.
6:51
And then I think we're good for right now.
6:55
And then we need to close
our FormSet factory.
7:02
Let's do an extra 2 for right now.
7:10
All right, so that's got our form,
all that kinda stuff, so
7:12
now let's handle our formset in a view.
7:16
The two views that we're gonna need
to edit are the edit_question and
7:20
the create_question.
7:24
So in create_question, right here
if we do this form = form_class(),
7:27
let's add in answer_forms =
forms.AnswerInlineFormSet.
7:33
And since we're creating a question,
this question has no answers.
7:39
So our queryset is going to be
models.Answers.objects.none().
7:46
And that just says, hey give me
a blank queryset, which is fine.
7:54
So, let's look down here.
7:59
So inside of our POST
we get our form class.
8:01
We also need to get our
answer_forms again.
8:05
So answer_forms is gonna
be forms.InlineFormSet,
8:09
and I realize I forgot
the word Answer on there.
8:14
And our request.POST goes into that.
8:18
And our queryset is, once again,
8:21
models.Answer.objects.none() because
we don't have any.
8:25
So if the form.is.valid and
8:31
if the answer_forms are valid,
then we wanna do this.
8:34
We wanna create the question.
8:40
We wanna actually create and
save that question.
8:41
Then we wanna do answers
= answer_forms.save,
8:44
and again, commit = False.
8:49
This should look very familiar to you.
8:52
And then for answer in answers,
answer.question = question, answer.save().
8:54
Cool, so nothing too special there.
9:03
All right, let's go ahead and
do the edit one as well.
9:07
And then we will finish this up.
9:10
Oh, we do need to do
'formset' : answer_forms.
9:14
We gotta send that out to the template.
9:19
Okay now we need to edit
our edit_question view.
9:21
And this actually ends up being pretty
similar to our create_question view.
9:25
So down here where we do the form_class,
9:29
we need to add in the answer_forms
= forms.AnswerInlineFormSet.
9:33
And our queryset here is
form.instance.answer_set.all().
9:41
And in here we do the same idea.
9:49
You know what,
9:52
let's just copy and paste.
9:55
The one thing different here is
we wanna pass in request.POST.
10:01
And I have to spell request correctly.
10:05
All right, so if the form is valid and
10:07
answer_forms is valid,
then we wanna do form.save.
10:11
And we could actually just
do answer_forms.save().
10:16
But since we might have new answer_forms,
10:22
new answers being filled out,
10:27
we need to do our old friend here of,
10:31
answers = answer_forms.save(commit=False)
for answer in answers.
10:36
answer.question = question answer.save().
10:45
And that just makes sure that
they all have that same thing.
10:51
And we need to send back our formset for
answer_forms.
10:55
And I think we're good.
11:01
Let's give it a try.
11:02
So let's go to Edit our question.
11:03
Here's our question form.
11:07
And then here's our inline formset.
11:08
All right let's add a new one here.
11:11
And let's just say ASCII.
11:13
And hit Save.
11:18
Let's make sure that it updates correctly.
11:19
Okay so that says ASCII.
11:21
Okay now let's add a new one.
11:23
Let's add Emoji only.
11:24
Wow, some days I cannot type.
11:30
And now let's hit Save.
11:33
And now we've got that
one in there as well.
11:35
So cool, we have inline formsets and
that means we can go back
11:37
to our question_form.html and
we can take off this answers thing.
11:42
Because we don't need that anymore,
11:49
no more button down here that says
Answers, cuz we don't need to go there.
11:51
We can get rid of that view and
that template and all of that.
11:57
Again, this isn't something I've done
very often in my own Django career.
12:01
Another area that isn't super
common is Django's form wizard.
12:05
I'll link to that in the teacher's
notes if you want to check it out.
12:08
Neither of these things, formsets or form
wizards, are everyday needs with Django.
12:11
But they're really handy
when the need arises.
12:16
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