从数据库唯一验证中验证唯一值

如果正在输入现有值，则有些人会出现有关错误消息未显示的问题。例如，我不允许用户注册现有的电子邮件。

视图

<?php
......................    
    
    <?= $form->field($modelUser, 'email')->textInput(['class'=>'form-control','placeholder'=>'Email']) ?>
......................    

调节器

<?php
use yii\web\Response; // important lines
use yii\widgets\ActiveForm; // important lines
        
.
.// Your code
.
        
public function actionSignup() 
{
            
    $modelUser = new User();
        
    //Add This For Ajax Validation 
    if(Yii::$app->request->isAjax && $modelUser->load(Yii::$app->request->post())){
        Yii::$app->response->format = Response::FORMAT_JSON;
        return ActiveForm::validate($modelUser);
    } 
    if ($modelUser->load(Yii::$app->request->post()) && $modelUser->save()) {
        return $this->redirect(['someplace nice']);
    }
    return $this->render('update', [
        'modelUser' => $modelUser,
    ]);            
}

模型

public function rules()
{
    return [
        ..............
        ['email', 'unique', 'message'=>'Email already exist. Please try another one.'],
        ...........
    ]
}