项目场景：

layui文件（excel）上传 保存附件 读取文件内容，进行数据库更新 

分析：

提示：前端js：

layui.use('upload', function () {
        var upload = layui.upload;
        //执行实例
        var uploadInst = upload.render({
            elem: '#UploadChange' //绑定元素
            , accept: 'file'
            , url: "/SampleRepository/UploadChange" //上传接口
            , data: {

            }
            , before: function (obj) { //obj参数包含的信息，跟 choose回调完全一致，可参见上文。
                layer.load(); //上传loading
            }
            , done: function (data) {
                //上传完毕回调
                alert(data.res);
                ReloadTable();
                layer.closeAll('loading'); //关闭loading
            }
            , error: function (error) {
                //请求异常回调
                alert(error.res);
                layer.closeAll('loading'); //关闭loading
            }
        });
        uploadInst.reload({
            accept: 'file'
        });
    });

提示：后端C#代码

public ActionResult UploadChange()
        {
            var file = Request.Files[0];
            try
            {
                string fileName = file.FileName;
                string name = DateTime.Now.ToString("yyyyMMdd_HHmmss_") + fileName;
                string filePath = HttpContext.Server.MapPath("~/File/信息导入/") + name;
                byte[] buffer;
                var inputStream = file.InputStream;
                int readLength = Convert.ToInt32(inputStream.Length);
                buffer = new byte[readLength];
                inputStream.Seek(0, SeekOrigin.Begin);
                inputStream.Read(buffer, 0, readLength);
                using (var outputSteam = new FileStream(filePath, FileMode.Create, FileAccess.Write))
                {
                    outputSteam.Seek(0, SeekOrigin.Begin);
                    outputSteam.Write(buffer, 0, buffer.Length);
                }
                NPIOUser aaa = new NPIOUser();
                DataSet srcDS = new DataSet();
                srcDS = aaa.NPIOExcelToDS(filePath, "汇总表");string ExNumber = "";
                int ExCount = 0;
                for (int i = 0; i < srcDS.Tables[0].Rows.Count; i++)
                {
                    string SampleNumber = "";
                    string SampleState = "";
                    string ChangeNumber = "";
                    DateTime OutDate = new DateTime();

                    SampleNumber = srcDS.Tables[0].Rows[i]["编号"].ToString();
                    SampleState = srcDS.Tables[0].Rows[i]["状态"].ToString();
                    ChangeNumber = srcDS.Tables[0].Rows[i]["单号"].ToString();
                    OutDate = Convert.ToDateTime(srcDS.Tables[0].Rows[i]["日期"]);

                    RepositorySampleData data = SampleRepository.RepositorySampleDatas.FirstOrDefault(p => p.编号 == SampleNumber);
                    if (data != null)
                    {
                        if (SampleState.Trim()!="")
                        {
                            data.状态 = SampleState;
                        }
                        if (ChangeNumber.Trim() != "")
                        {
                            data.单号 = ChangeNumber;
                        }
                        if (OutDate != null)
                        {
                            data.时间 = OutDate;
                        }
                        SampleRepository.UpdateSample(data);
                    }
                    else
                    {
                        ExCount++;
                        ExNumber += SampleNumber + ";";
                    }}
                if (ExNumber.Length == 0)
                {
                    return Content(JsonConvert.SerializeObject(new { res = "数据导入成功。无异常数据" }));
                }
                else
                {
                    return Content(JsonConvert.SerializeObject(new { res = "数据导入成功。存在" + ExCount + "条异常数据未导入，机身编号为:" + ExNumber }));
                }
            }
            catch (Exception error) { return Content(JsonConvert.SerializeObject(new { res = "出现异常情况，数据不完整，请联系开发人员。" })); }

        }

解决方案：

提示：layui文件（excel）上传 保存附件 读取文件内容，进行数据库更新

public void UpdateSample(RepositorySampleData Samples)
        {
            SampleDataContext.Entry<RepositorySampleData>(Samples).State = EntityState.Modified;
            try
            {
                SampleDataContext.SaveChanges();
            }
            catch (Exception error)
            {
            }
        }