element-ui el-upload组件 onchange事件 传自定义参数，具体可以参考如下：
<el-col :span="4" :offset="index == 0? 2:0" v-for="(item, index) in goodImgList">
<el-upload
action=""
:limit="1"
:on-preview="(file) => {onHandleImgPreview(file, index)}"
:on-change="(file) => {onHandleChange(file, index)}"
:http-request="requestUpload"
list-type="picture-card"
:on-remove="(file) => {onHandleRemove(file, index)}"
:class="{disabled:item.uploadDisabled}"
:file-list="fileList">
<i class="el-icon-camera"></i>
</el-upload>
<el-dialog :modal-append-to-body="false" :visible.sync="item.imgVisible" width="30%">
<img width="100%" :src="item.dialogImageUrl" alt="图片未找到"/>
</el-dialog>
</el-col>
js对应代码：
onHandleImgPreview(file, index){
console.info(index)
console.info(file)
},
onHandleChange(file, index){
console.info(index)
console.info(file)
},
onHandleRemove(file, index){
console.info(index)
console.info(file)
}
