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Form Rendering and Form Variables

Let's talk form rendering.

Sure, things looks nice right now, especially considering we're rendering all the fields in one line!

The problem? First, we can't change the order of the fields. And second, we won't be able to control the labels or anything else that we're going to talk about.

Using form_row

So, in reality, I don't use form_widget to render all my fields at once. Replace this with a different function: form_row and pass it genusForm. and then the name of one of the fields - like name:

43 lines app/Resources/views/admin/genus/new.html.twig
... lines 1 - 22
{% block body %}
<div class="container">
<div class="row">
<div class="col-xs-12">
... lines 27 - 28
{{ form_start(genusForm) }}
{{ form_row(genusForm.name) }}
... lines 31 - 37
{{ form_end(genusForm) }}
</div>
</div>
</div>
{% endblock %}

Since this form has 1, 2, 3, 4, 5, 6 fields, I'll copy that and paste it six times. Now, fill in all the field names: subFamily, speciesCount, funFact, isPublished and firstDiscoveredAt:

43 lines app/Resources/views/admin/genus/new.html.twig
... lines 1 - 22
{% block body %}
<div class="container">
<div class="row">
<div class="col-xs-12">
... lines 27 - 28
{{ form_start(genusForm) }}
{{ form_row(genusForm.name) }}
{{ form_row(genusForm.subFamily) }}
{{ form_row(genusForm.speciesCount) }}
{{ form_row(genusForm.funFact) }}
{{ form_row(genusForm.isPublished) }}
{{ form_row(genusForm.firstDiscoveredAt) }}
... lines 36 - 37
{{ form_end(genusForm) }}
</div>
</div>
</div>
{% endblock %}

Refresh! OMG - it's the exact same thing as before!!! This is what form_widget was doing behind the scenes: looping over the fields and calling form_row.

All the Form Rendering Functions

So, at this point, you're probably asking:

What else can I do? What other functions are there? What options can I pass to these functions?

Look, I don't know! But I bet Google does: search for "form functions twig" to find another reference section called Form Function and Variable Reference.

Ah hah! This is our cheatsheet!

First - we already know about form_row: it renders the 3 parts of a field, which are the label, the HTML widget element itself and any validation errors.

If you ever need more control, you can render those individually with form_widget, form_label and form_errors. Use these instead of form_row, only when you need to.

Form Variables

Now notice, most of these functions - including form_row - have a second argument called "variables". And judging by this code example, you can apparently control the label with this argument.

Listen closely: these "variables" are the most powerful part of form rendering. By passing different values, you can override almost every part of how a field is rendered.

So what can you pass here? Scroll down near the bottom to find a big beautiful table called Form Variables Reference.

This gives you a big list of all the variables that you can override when rendering a field, including label, attr, label_attr, and other stuff.

To show this off, find the speciesCount field and add a second argument set to {} - the Twig array syntax. Override the label variable: set it to Number of Species:

45 lines app/Resources/views/admin/genus/new.html.twig
... lines 1 - 22
{% block body %}
<div class="container">
<div class="row">
<div class="col-xs-12">
... lines 27 - 28
{{ form_start(genusForm) }}
... lines 30 - 31
{{ form_row(genusForm.speciesCount, {
'label': 'Number of Species'
}) }}
... lines 35 - 39
{{ form_end(genusForm) }}
</div>
</div>
</div>
{% endblock %}

Refresh! It's just that easy.

The Amazing Form Profiler

There's one huge form tool that we haven't looked at yet. Your web debug toolbar should have a clipboard icon. Click it.

This is the profiler for your form, and it's packed with stuff that's going to make your form life better. If you click speciesCount, you can see the different data for your species - which isn't too interesting on this blank form. You can see any submitted data and all of the variables that can be passed to the field.

It turns out, the reference section we looked at has most of the variables but this will have all of them. This is your place to answer:

What are the values for my variables? And, what can I override?

This also shows you "Resolved Options": these are the final values of the options that can be passed as the third argument to the add() function.

CSRF Protection

Oh, and check out this _token field. Do you remember adding this?

Hopefully not - because we never did! This is a CSRF token that's automatically added to the form. It's rendered for us when we call form_end and validated behind the scenes along with all the other fields. It's free CSRF protection.

Leave a comment!

  • 2016-11-17 Terry Caliendo

    Got it... As always, thanks for the informative response!

  • 2016-11-14 weaverryan

    Yo Terry!

    You're totally right as usual :). You *can* change the order... you just can't do it from inside of the template (only from inside the form class like you added here). This is an "accidental" feature... meaning it's not in purpose that it renders in the same way that you build your fields. That being said, it's not going to change ever, so this *is* a reliable way to control the order of your fields.

    The next question is, should you do this? It depends: if you're a one-(wo)man army, maybe! But if you may ever work with frontend people, then the more display logic you can put into the template, the better: we want to simply be able to tell them to open "form.html.twig" to make changes, not also to need to hunt down a form class or controller :).

    Cheers!

  • 2016-11-13 Terry Caliendo

    You say in the video that when using the form_widget you can't change the *order* of the fields. However according to my tests it does appear that the order in which you add the fields to the form builder is the order they appear on the form.

    Question Title displays First on the Form

            $form = $this->createFormBuilder($FlowObject)
    ->add('QuestionTitle')
    ->add('QuestionInformation')
    ->getForm();

    VS

    Question Title displays 2nd on the Form

            $form = $this->createFormBuilder($FlowObject)
    ->add('QuestionInformation')
    ->add('QuestionTitle')
    ->getForm();

  • 2016-10-01 Peter Stephens

    Never mind. It was wrong file.

  • 2016-10-01 Peter Stephens

    Hmmmm.... No auto complete here?