如何将从另一个模型中获取角色数组传递到laravel中注册表单

// User.php
class User extends Authenticatable
{
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }
}

// Role.php
class Role extends Model
{
    public function users()
    {
        return $this->belongsToMany(User::class);
    }
}

$roles = Role::all()->pluck('id');

public function showRegistrationForm()
{
    $roles = Role::all()->pluck('id');
    return view('registration.form', compact('roles'));
}

<form action="{{ route('register') }}" method="POST">
    @csrf
    <label for="name">Name:</label>
    <input type="text" id="name" name="name">

    <label for="email">Email:</label>
    <input type="email" id="email" name="email">

    <label for="password">Password:</label>
    <input type="password" id="password" name="password">

    <label for="role">Role:</label>
    <select id="role" name="role">
        @foreach ($roles as $roleId)
            <option value="{{ $roleId }}">{{ Role::find($roleId)->name }}</option>
        @endforeach
    </select>

    <button type="submit">Register</button>
</form>

public function register(Request $request)
{
    $validatedData = $request->validate([
        'name' => 'required|string|max:255',
        'email' => 'required|email|unique:users',
        'password' => 'required|min:8|confirmed',
        'role' => 'required',
    ]);

    $user = User::create([
        'name' => $validatedData['name'],
        'email' => $validatedData['email'],
        'password' => Hash::make($validatedData['password']),
    ]);

    $user->roles()->attach($validatedData['role']);

    return redirect()->route('home')->with('success', 'User registered successfully!');
}

$roles = Role::all()->pluck('id');
if (empty($roles)) {
    // 处理错误
}

$role = Role::find($validatedData['role']);
if (!$role) {
    // 处理错误
}