vue3 upload组件,在弹出文件选择窗口之前做操作

<el-upload

        :disabled="showUpload"

        class="upload-demo"

        ref="uploadRef"

        action="#"

        :multiple="multiple == 'image'?true:false"

        :show-file-list="false"

        :before-upload="beforeUpload"

        :on-exceed="handleExceed"

        :limit="dialogParam.limit"

        :accept="dialogParam.accept"

        :http-request="uploadFiles"

      >

        <el-button @click="handleUpload" type="primary">上传</el-button>

         <span v-if="dialogParam.type == 'image'" style="margin-left:10px">图片规格：jpg格式、大小15mb内</span>

         <span v-else style="margin-left:10px">视频规格：mp4、mv4格式，大小300mb内</span>

      </el-upload>

//  点击上传前做判断

const handleUpload = async() => {

  if(dataList.value.length>=30){

    ElMessageBox.alert('待添加区图片不能超过30张', '提示', {

      confirmButtonText: 'OK',

    })

    return false

  }else{

    showUpload.value = false

  }

}