Field Types and Options

So far, we set the property name of the form fields and Symfony tries to guess the best field type to render. Since isPublished is a boolean in the database, it guessed a checkbox field:

But obviously, that's not always going to work.

Google for "Symfony form field types", and find a document called Form Types Reference.

These are all the different field types we can choose from. It's got stuff you'd expect - like text and textarea, some HTML5 fields - like email and integer and some more unusual types, like date, which helps render date fields, either as three drop-downs or a single text field.

Right now, isPublished is a checkbox. But instead, I'd rather have a select drop-down with "yes" and "no" options. But... you won't see a "select" type in this list. Instead, it's called ChoiceType.

Using ChoiceType

ChoiceType is a little special: it can render a drop-down, radio buttons or checkboxes based on what options you pass to it. One of the options is choices, which, if you look down at the example, you can see controls the actual items in the drop-down.

Let's use this! In GenusFormType, the optional second argument to the add function is the field type you want to use. Set it to ChoiceType::class:

The third argument is an array of options to configure that field. What can you pass here? Well, each field type has different options... though there are a lot of options shared by all types, like the ability to customize the label.

Either way, the reference section will tell you what you can use. Pass in the choices option and set that to an array. Add Yes mapped to true and No mapped to false. The keys - Yes and No will be the text in the drop down:

The values - true and false will be the value that's passed to setIsPublished() if that option is chosen.

Try it out! Head back to the form and refresh! Perfect.

The EntityType

Let's keep going with this. This subFamily field is also a drop-down. So that's probably being guessed as a ChoiceType, right? Almost. Check out the EntityType. This is just like the ChoiceType, except it's really good at fetching the options by querying an entity.

In this case, it's automatically querying for the SubFamily entity: it guessed which type to use and auto-configured it. And yeah, I know - these sub-families are totally silly. They're actually just the last names of people - coming from the Faker library - I was being lazy.

Form Field Options

But I do have one problem with this EntityType field: it auto-selects the first option. That's lame - I'd rather have an option on top that says "Choose a Sub-Family".

Check out the options for EntityType: there's one called placeholder. Click to read more about that. Yes! This is exactly what we want!

Open the form class back up. We know that Symfony is guessing the EntityType for the subFamily field. We could now manually pass EntityType::class as the second argument. But don't! Pass null instead. Now, add a placeholder option set to Choose a Sub-Family:

But wait, why did I pass null as the second argument? Well first, because I can! I can be lazy here: if I pass null, Symfony will guess the EntityType. That's cool.

Second, when you use the EntityType, there's a required option called class. Let me show you an example: 'class' => 'AppBundle:User'. You have to tell it which entity to query from. But if you let Symfony guess the field type for you, then it will also guess any options it can, including this one. So by being lazy and passing null, it will continue to guess the field type and a few other options for me, like class.

Anyways, go back, refresh, and there it is. Here are the key takeaways. First, you have a giant dictionary of built-in form field types. And second: you configure each field by passing a third argument to the add() function.

Now, how could we further control the query that's made for the SubFamily options? What if we need them to be listed alphabetically?