type: mixeddefault: Defaults to field of the underlying structure.
When you create a form, each field initially displays the value of the
corresponding property of the form’s domain data (e.g. if you bind an object to
the form). If you want to override this initial value for the form or
an individual field, you can set it in the data option:
The data option always overrides the value taken from the domain data
(object) when rendering. This means the object value is also overridden when
the form edits an already persisted object, causing it to lose its
persisted value when the form is submitted.
Form data transformers will still be
applied to the empty_data value. This means that an empty string will
be cast to null. Use a custom data transformer if you explicitly want
to return the empty string.
This option allows you to modify the target of a validation error.
Imagine you have a custom method named matchingCityAndZipCode() that validates
whether the city and zip code match. Unfortunately, there is no matchingCityAndZipCode
field in your form, so all that Symfony can do is display the error on top
of the form.
With customized error mapping, you can do better: map the error to the city
field so that it displays above it:
Here are the rules for the left and the right side of the mapping:
The left side contains property paths;
If the violation is generated on a property or method of a class, its
path is the propertyName;
If the violation is generated on an entry of an array or ArrayAccess
object, the property path is [indexName];
You can construct nested property paths by concatenating them, separating
properties by dots. For example: addresses[work].matchingCityAndZipCode;
The right side contains the names of fields in the form.
By default, errors for any property that is not mapped will bubble up to the
parent form. You can use the dot (.) on the left side to map errors of all
unmapped properties to a particular field. For instance, to map all these
errors to the city field, use:
By default form fields read from and write to the properties with the same names
in the form’s domain object. The property_path option lets you define which
property a field reads from and writes to. The value of this option can be any
valid PropertyAccess syntax.
If you wish the field to be ignored when reading or writing to the object
you can set the property_path option to false, but using
property_path for this purpose is deprecated, you should use the