1子组件

成功

  ChangeRest(event, file){
   /*   console.log(event)
      console.log(file)*/
     /* console.log(URL.createObjectURL(file.raw))*/
      this.imageUrl = URL.createObjectURL(file.raw);
     /* this.imageUrl=event.tmp_url
      console.log(this.imageUrl)*/
      console.log(1)
      this.eventSave=event
      console.log(this.eventSave)
      this.$emit("ChangeLest",this.eventSave)
    },

2父组件

 changeRest1(val){
      console.log(2)
      console.log(val)
      this.preview=val.tmp_url
      console.log(this.preview)
      this.form.thumbnail=val.relativepath+val.name

    }

3预览效果

通过两个不同的值实现预览 下面做个预览 库里面加个字段即可