手动触发el-upload的上传事件

<el-upload v-show="false" ref="videoUpload" v-loading="loading" style="text-align: center;" drag
     :action="uploadVideoConfig.uploadUrl" accept="video/*" :name="uploadVideoConfig.name"
     :before-upload="onBeforeUploadVideo" :on-success="onSuccessVideo" :on-error="onErrorVideo" :multiple="false">
     <i class="el-icon-upload"></i>
     <!--这个按钮要设置类名，我这里是upload-video  -->
     <el-button size="small" type="primary" class="upload-button">点击上传</el-button>
     <div class="el-upload__tip" slot="tip">只能上传MP4文件，且不超过{{ uploadVideoConfig.maxSize }}M</div>
 </el-upload>
 <!-- 这个按钮添加一个点击事件，来触发上传事件 -->
 <el-button size="small" type="primary" @click="uploadVideo">点击上传</el-button>
export default {
    methods: {
        uploadVideo() {
        	//这里通过元素选择器来手动触发点击事件
        	this.$refs.videoUpload.$el.querySelector('.uploac-button').click();
        }
    },
}