Yii2 如何在控制器给模型赋初值？ [ 2.0 版本 ]

因为你的 FileUpload 继承的 Object 类，Object 类在实例化的时候，就会调用init() 方法

public function __construct($config = [])
{
    if (!empty($config)) {
        Yii::configure($this, $config);
    }
    $this->init();
}

所以你现在的报错是在new FileUpload() 就报错了， 你下面修改类的属性都还没有执行，并不是不能修改！
如果你要修改类的属性，直接在new FileUpload() 时候传递一个数组就可以了(属性对应属性值)

$model = New FileUpload([
            'fileInputName' => 'name',
            'allowType'     => ['jpg', 'png', 'gif', 'txt'],
            'mimetype'      => ['image/jpeg', 'image/bmp', 'image/gif', 'image/png', 'image/pjpeg', 'image/x-png', 'text/plain'],
            'savePath'      => Yii::getAlias('@frontend/web/upload/file')
        ]);

这样就可以了!

另外：个人建议 FileUpload 需要将功能拆分，上传验证交给 model, FileUpload 只负责调用 model 验证，以及处理上传路径问题

附代码：

1. 上传model

<?php

namespace frontend\models;

use yii\base\Model;

class UploadForm extends Model
{
    public $name;

    public $file;

    /**
     * 设置验证场景
     *
     * @return array
     */
    public function scenarios()
    {
        return [
            'name' => ['name'],
            'file' => ['file'],
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function rules()
    {
        // 我这里是偷懒的写法,就是多个上传字段，使用一个上传验证类, 只要添加验证场景和验证字段规则就好了
        return [
            [
                ['name'],
                'file',
                'extensions' => ['jpg', 'png', 'gif', 'txt'],
                'maxSize'    => 1024100000,
//                'checkExtensionByMimeType' => false, // 要不要验证 mimeTypes 类型
                'mimeTypes'  => ['image/jpeg', 'image/bmp', 'image/gif', 'image/png', 'image/pjpeg', 'image/x-png', 'text/plain'],
                'on'         => 'name',
            ],
            [
                ['file'],
                'image',
                'extensions' => ['jpg', 'png', 'gif'],
                'maxSize'    => 1024100000,
                'on'         => 'file',
            ]
        ];
    }
}

1. FileUpload 代码

<?php

namespace frontend\models;

use yii;
use yii\base\Object;
use yii\helpers\FileHelper;
use yii\web\UploadedFile;

class FileUpload extends Object
{
    /**
     * @var \yii\base\Model 处理的model
     */
    public $model;

    /**
     * @var string 上传文件表单名称
     */
    public $fileInputName = 'file';

    /**
     * @var string 图片保存绝对路径
     */
    public $savePath;

    /**
     * @var string 文件访问路径前缀
     */
    public $urlPathPrefix = '/upload/images';

    /**
     * @var UploadedFile 上传文件处理类
     */
    private $uploadFile;

    /**
     * @var string 文件保存路径
     */
    private $filePath;

    /**
     * @var string 文件访问路径
     */
    private $urlPath;

    /**
     * @return array|void
     * @throws yii\base\Exception
     */
    public function init()
    {
        if (!$this->savePath) {
            $this->savePath = Yii::getAlias('@frontend/web/upload/images');
        }

        // 目录不存在创建
        $this->savePath = rtrim($this->savePath, '/');
        if (!file_exists($this->savePath) && !FileHelper::createDirectory($this->savePath)) {
            throw  new yii\base\Exception('没有权限创建' . $this->savePath);
        }

        if (empty($this->model) || !($this->model instanceof Model)) {
            throw  new yii\base\Exception('没有传递上传文件类');
        }

        // 上传文件接收
        $strField               = $this->fileInputName;
        $this->model->$strField = $this->uploadFile = UploadedFile::getInstanceByName($this->fileInputName);
        if (empty($this->uploadFile)) {
            throw  new yii\base\Exception('没有上传文件');
        }

        // 上传文件验证
        if (!$this->model->validate()) {
            throw  new yii\base\Exception($this->model->getFirstError($strField));
        }

        list($path, $datePath) = $this->createDir($this->savePath);
        $fileName = time() . mt_rand(1000, 9999) . '.' . $this->uploadFile->getExtension();

        $this->filePath = $path . $fileName;
        $this->urlPath  = rtrim($this->urlPathPrefix, '/') . '/' . $datePath . '/' . $fileName;
    }

    /**
     * 根据时间创建目录
     *
     * @param $path
     *
     * @return array
     *
     * @throws yii\base\Exception
     */
    public function createDir($path)
    {
        $datePath = date('Y') . '/' . date('md');
        $path     = $path . '/' . $datePath . '/';
        if (!file_exists($path)) {
            FileHelper::createDirectory($path);
        }


        return [$path, $datePath];
    }

    public function save()
    {
        return $this->uploadFile->saveAs($this->filePath);
    }

    public function getUrlPath()
    {
        return $this->urlPath;
    }
}

1. 控制器调用

public function actionFileUpload()
    {
        try {
            $model = New FileUpload([
                'fileInputName' => 'name',
                'model'         => new UploadForm(['scenario' => 'name']),
                'savePath'      => Yii::getAlias('@frontend/web/upload/file'),
                'urlPathPrefix' => '/upload/file'
            ]);

            if (!$model->save()) {
                throw new \Exception('上传文件失败');
            }

            return $this->asJson([
                'code' => 1,
                'msg'  => '上传文件成功',
                'data' => ['url' => $model->getUrlPath()]
            ]);
        } catch (\Exception $e) {
            return $this->asJson(['code' => 0, 'msg' => $e->getMessage()]);
        }
    }