Symfony 2 - 表單錯誤 - 獲取錯誤類型

Question

是否可以在表單提交後檢查違反了哪個約束條件？ 我想在提交後做出特定的操作，但只有在出現特定的錯誤時（自定義約束）。

Answer 1

是的，你可以。這不是一個很乾淨的方式（因爲它是一個非常自定義的表單用例），但它是可能的。

這是一個簡單的代碼示例。它可能無法處理一些邊緣情況，但適用於我的表單：

//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; 
     } 

    }