Symfony 2-表单错误-获取错误类型

是否可以检查表单提交后违反了哪个约束？

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我想在提交后执行特定操作，但仅当出现特定错误时（自定义约束）。

可以。这不是一种非常干净的方式（因为这是一个非常定制的表单用例），但这是可能的

下面是一个简单的代码示例。它可能无法处理某些边缘情况，但适用于我的表单：

    //You can get errors from form like this:
    $errors = $form->getErrors(true);

    // Or like this if you want to check a particular field of your form
    $errors = $form->get('someField')->getErrors(true);

    //Now you have to iterate them and check 
    //if it's the error that you're looking for
    foreach($errors as $error) {
        //From the error you can get the constraint that caused it.
        $constraint = $error->getCause()->getConstraint();

        //Check if the constraint is the instace of the class
        //that you're insterested in.
        //It's ISBN validator in my example.
        if($constraint instanceof Symfony\Component\Validator\Constraints\Isbn) {
            // do anything you want.
            break;
        }

    }

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是的，你可以。这不是一种非常干净的方式（因为这是一个非常定制的表单用例），但这是可能的

下面是一个简单的代码示例。它可能无法处理某些边缘情况，但适用于我的表单：

    //You can get errors from form like this:
    $errors = $form->getErrors(true);

    // Or like this if you want to check a particular field of your form
    $errors = $form->get('someField')->getErrors(true);

    //Now you have to iterate them and check 
    //if it's the error that you're looking for
    foreach($errors as $error) {
        //From the error you can get the constraint that caused it.
        $constraint = $error->getCause()->getConstraint();

        //Check if the constraint is the instace of the class
        //that you're insterested in.
        //It's ISBN validator in my example.
        if($constraint instanceof Symfony\Component\Validator\Constraints\Isbn) {
            // do anything you want.
            break;
        }

    }