OctoberCMS用户关联字段必填验证失效问题求助

Ah, I see the issue here—you're validating the relation name instead of the actual foreign key field that gets populated when you select a user in the backend. Let me break down how to fix this quickly:

Step 1: Update Your Validation Rules #

Change your $rules array to target the foreign key user_id instead of the relation name. This is the field that actually gets set when you pick a user via the backend relation picker:

/**
 * @var array Validation rules
 */
public $rules = [
    'user_id' => 'required'
];

Step 2: (Optional) Add Extra Rigor with an Existence Check #

If you want to make sure the selected user ID actually corresponds to a valid user in the database, extend the rule with exists:

public $rules = [
    'user_id' => 'required|exists:users,id'
];

(Note: users is the default table name for Rainlab User's User model—adjust this if you’ve customized the table name in your setup.)

Why This Works #

When you use the backend relation picker configured in your config_relation.yaml, it renders a field that submits the selected user’s ID to the user_id column in your model’s table. Your original rule targeted the user relation object, which hasn’t been loaded yet during the initial form submission—so the validation always failed, even when a user was selected.

By validating user_id directly, you’re checking the actual value that gets stored, which aligns perfectly with how the form data is processed.

内容的提问来源于stack exchange，提问作者Ronaldo Ribeiro de Sousa