Php Symfony2表单中EntityType字段的动态组

我正在尝试开发一个表格，让学生从几个小组中选择课程。其定义如下：

• 课程有名称/描述/学时
• 课程属于对学时有名称/说明/限制的组（例如，您必须从该组中选择5学时，或者您最多只能从该组中选择10学时）
• 课程组被组织成一个项目，可以有其他领域

因此，我希望表格允许学生选择课程，但课程是按分组组织的，并有关于选择多少课程的说明。学分部分将使用自定义验证规则进行验证

下面是我想到的代码的想法（省略了许多名称空间/原则映射等）

实体有点像这样：

class Offering
{
    // has multiple CourseGroups
    private $groups;
}

class CourseGroup
{
    // which Offering it belongs to
    private $offering;
    private $name;
    private $maxHours;
}

class Course
{
    // which CourseGroup it belongs to
    private $group;
    private $name;
    private $hours;
}

// User submits an application with chosen courses from multiple groups
class Application
{
    // ...
    private $courses;
}

// Joins the Applications to Courses (N to N)
class ApplicationCourse
{
    // which Application
    private $application;
    // which Course
    private $course;
}

但我想弄清楚如何把它变成一种形式。我不介意将表单绑定到一个数组，然后将其排序，将其放入

应用程序中

class ApplicationType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            // ...other fields
        ;

        // Add the groups of courses to choose
        $builder->addEventListener(
            FormEvents::PRE_SET_DATA,
            function(FormEvent $event) use ($offering) {
                $form = $event->getForm();

                // Here I would like to add 1 EntityType per Offering
                // The EntityType allows the user to select multiple Courses within that group
                $i = 0;
                foreach ($offering->groups as $group) {
                    // Maybe add the $group as a static block in the twig template here
                    // Ideally the form should show the group name/description

                    // I'll probably borrow from this class https://github.com/genemu/GenemuFormBundle/blob/master/Form/Core/Type/PlainType.php

                    // This adds a group of checkboxes to select a course from this group
                    $form->add('course_'.$i, 'entity', array(
                        'class' => 'Acme\DemoBundle\Entity\Course',
                        'property' => 'name',
                        'multiple' => true,
                        'expanded' => true,
                        'query_builder' => function(EntityRepository $er) use ($group) {
                            // imagine this ia a query that selects all courses in the $group
                            return $er->createGroupCoursesQueryBuilder($group);
                        },
                    );
                    $i++;
                }
            }
        );
    }

    public function getName()
    {
        return 'task';
    }
}

最后，我想要一个如下所示的表单：

class Offering
{
    // has multiple CourseGroups
    private $groups;
}

class CourseGroup
{
    // which Offering it belongs to
    private $offering;
    private $name;
    private $maxHours;
}

class Course
{
    // which CourseGroup it belongs to
    private $group;
    private $name;
    private $hours;
}

// User submits an application with chosen courses from multiple groups
class Application
{
    // ...
    private $courses;
}

// Joins the Applications to Courses (N to N)
class ApplicationCourse
{
    // which Application
    private $application;
    // which Course
    private $course;
}

科学：选择至少4个学时


[x] SCI100（2小时）
[]SCI101（2小时）
[]SCI102（2小时）

数学：选择至少4个学时


[]MTH100（4小时）
[x] MTH101（4小时）

{组名称}：{组描述}


[{选定？}]{课程名称}{课程时数}

等等

这种方法有效吗？有没有更好的方法，使我不必将表单绑定到数组，然后在验证后重新组装它？
看到这个答案后，解决方案实际上很简单

我刚刚定制了表单的呈现。最棒的是，我得到了Symfony表单的所有有用部分（数据绑定），但我可以完全自定义渲染

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('courses', 'entity', array(
            'class' => 'MyMainBundle:Course',
            'property' => 'name',
            'multiple' => true,
            'expanded' => true
        ))
        ->add('save', 'submit')
    ;
}

在细枝模板中有一个很酷的技巧，就是自己渲染它。我确实必须通过这几组课程

诀窍是使用
{%do form.courses.setRendered%}

{{ form_start(form) }}
    {{ form_errors(form) }}

    {% for group in academics.courseGroups %}
    <section>
        <h2>
            {{ group.name }}
        </h2>
        <p>{{ group.description }}</p>

        {% for course in group.courses %}
        <div class="form-group">
            <div class="course">
                <div class="checkbox">
                    <label for="my_mainbundle_application_course_courses_{{ course.id }}">
                        <input type="checkbox"
                               id="my_mainbundle_application_course_courses_{{ course.id }}"
                               name="my_mainbundle_application_course[courses][]"
                               value="{{ course.id }}"
                               {% if course.id in form.courses.vars.value and form.courses.vars.value[course.id] %}checked="checked"{% endif %}>
                        <span class="name">{{ course.name }}</span>
                        <span class="subject">({{ course.subject }})</span>
                        -
                        <span class="credits">{{ course.credits }} hours</span>
                    </label>
                </div>
            </div>
        </div>
        {% endfor %}
    </section>
    {% endfor %}

    {% do form.courses.setRendered %}
    {{ form_row(form.save) }}

{{ form_end(form) }}

{{form_start（form）}
{{form_errors（form）}}
{academics.courseGroups%中的组为%s}
{{group.name}
{{group.description}}

{组中课程的百分比。课程%}
{{course.name}
（{{course.subject}}）
-
{{course.credits}}小时
{%endfor%}
{%endfor%}
{%do form.courses.setRendered%}
{{form_行（form.save）}
{{form_end（form）}}
这些问题很有帮助：设置渲染属性的选项也很有帮助！