layui动态上传按钮点击无效

// 上传按钮
let result = $("<button type='button' class='layui-btn upload_btn' id=\""+row.id+"\"><i class='layui_icon'>&#xe67c;</i>测试文档</button>");
// 点击事件
uploadFn('#' + row.id)
// 在这里也可以
/*layui.use(['upload'],function(){
  let upload = layui.upload;
    upload.render({
            elem: '#' + row.id
            , url: '' // 上传接口
            , before: function (obj) {
                //预读本地文件示例，不支持ie8
                obj.preview(function (index, file, result) {
                    console.log(uploadImg);
                    $(showImg).attr('src', result); //图片链接（base64）
                });
            }
            , done: function (res) {
                //如果上传失败
                if (res.error > 0) {
                    return layer.msg('上传失败');
                }
                //上传成功
                if (res.error == 0) {
                    console.log(uploadImg)
                    $(uploadimd).html(res.url);
                    return layer.msg('上传成功');
                }
            }
            , error: function () {
                //演示失败状态，并实现重传
                var demoText = $('#demoText');
                demoText.html('<span style="color: #FF5722;">上传失败</span> <a class="layui-btn layui-btn-xs demo-reload">重试</a>');
                demoText.find('.demo-reload').on('click', function () {
                    uploadImg.upload();
                });
            }
        });
});*/

let upload;
layui.use(['upload'],function(){
  upload = layui.upload;
})
/**
 * 表格上传框
 * 上传文件
 */
function uploadFn(id){
  upload.render({
            elem: id
            , url: '' // 上传接口
            , accept:'file'
            , done: function (res,index,upload) {
               data.testFileUrl = res.url;
                data.testFileName = res.fileName;
            }
        });
}