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形式上的一对一关联？

发布于 2024-11-06 03:38:56 字数 53 浏览 6 评论 0原文

在symfony 2.0中，如何使用表单中的一对一关联创建下拉列表？你们能举个很好的例子吗？

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装迷糊 2024-11-13 03:38:57

我会尽力以我理解的方式回答你的问题。假设我有一个绑定到单个大学对象的Faculty 对象。因此，在用于创建或编辑教师的表单中，我显示数据库中所有大学的组合框，用户可以从中选择一所。有一种特殊的 Symfony 字段类型可以做到这一点：实体类型。下面是我在用于创建教师表单的 FacultyType 对象中使用的 buildForm 方法的代码：

// Application\AcmeBundle\Form\Type\FacultyType
public function buildForm(FormBuilder $builder, array $options)
{
    $builder->add('name');
    $builder->add('university', 'entity', array(
        // The class of the entity used as a combo box item
        'class' => 'AcmeBundle:University',

        // The property of the entity displaying the entity as text
        'property' => 'name',

        // The query builder used to populate the combo box, accepts
        // a QueryBuilder object or a \Closure like below 
        'query_builder' => function(EntityRepository $repository) {
            // This will return a query builder selecting all universities
            return $repository->createQueryBuilder('u');
        }
    ));
}

注意：还可以为实体字段设置其他属性类型，我邀请您查看此页面有关它的更多信息。

渲染后，这将显示一个组合框，其中包含我在数据库中设置的所有大学。当用户保存表单时，选择的大学将被分配给通过设置器绑定到表单的教员对象。您可能可以呈现一个下拉列表而不是组合框。如果您需要选择多个实体，字段类型实体的'multiple' 选项可能会很有用。

话虽这么说，我展示的示例不是一对一关系，而是 Faculty 对象的多对一关系和 University< 的一对多关系。 /代码> 对象。一对一关系更像是大学具有唯一地址的关系。在这种情况下，组合框不会有用，因为大学只能有一个地址，因此子表单会更合适。如果它有多个地址，那么它就成为一对多的关系，就像大学与其院系之间的关系一样。

不确定这是否能正确回答您的问题，但我希望它能引导您找到最终的解决方案。

问候，
马特

I will try to answer your question the way I understand it. Let's say I have a Faculty object bound to a single University object. So in the form used to create or edit a faculty, I display a combo box of all the university in the database and the user choose one among them. There is one special Symfony field type that does exactly this: the entity type. Below is the code of the buildForm method that I use in my FacultyType object used to create the faculty form:

// Application\AcmeBundle\Form\Type\FacultyType
public function buildForm(FormBuilder $builder, array $options)
{
    $builder->add('name');
    $builder->add('university', 'entity', array(
        // The class of the entity used as a combo box item
        'class' => 'AcmeBundle:University',

        // The property of the entity displaying the entity as text
        'property' => 'name',

        // The query builder used to populate the combo box, accepts
        // a QueryBuilder object or a \Closure like below 
        'query_builder' => function(EntityRepository $repository) {
            // This will return a query builder selecting all universities
            return $repository->createQueryBuilder('u');
        }
    ));
}

Note: There are other properties that can be set for the entity field type, I invite you to take a look at this page for more information on it.

Rendered, this will show a combo box with all the universities I have set in the database. When the user save the form, the university chose is assigned to the faculty object bound to the form via a setter. You could probably render a drop-down list instead of a combo box. If you need to select multiple entities, the 'multiple' option of the field type entity could be useful.

This being said, the example I showed is not a One-to-One relation but rather a Many-to-One for the Faculty object and a One-to-Many for the University object. A One-to-One relation would be something more like a relation where a University has a unique Address. In this case, a combo box wouldn't be useful since the university can only have one adress so a sub-form would be more appropriate. If it has many adresses, then it becomes a One-to-Many relation like the relation between the university and its faculties.

Not sure if this will answer your question correctly but I hope it will lead you to a final solution.

Regards,
Matt

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