Asp.net MVC实现生成Excel并下载功能

/// <summary>
 /// 辅助传输StatusMessage数据
 /// </summary>
 [Serializable]
 public sealed class StatusMessageData
 {
  private StatusMessageType messageType;
  /// <summary>
  /// 提示消息类别
  /// </summary>
  public StatusMessageType MessageType
  {
   get { return messageType; }
   set { messageType = value; }
  }

  private string messageContent = string.Empty;
  /// <summary>
  /// 信息内容
  /// </summary>
  public string MessageContent
  {
   get { return messageContent; }
   set { messageContent = value; }
  }

  private object data;

  /// <summary>
  /// 数据 
  /// </summary>
  public object Data
  {
   get { return data; }
   set { data = value; }
  }
  /// <summary>
  /// 构造器
  /// </summary>
  /// <param name="messageType">消息类型</param>
  /// <param name="messageContent">消息内容</param>
  public StatusMessageData(StatusMessageType messageType, string messageContent, object data)
  {
   this.messageType = messageType;
   this.messageContent = messageContent;
   this.data = data;
  }
  public StatusMessageData(StatusMessageType messageType, string messageContent)
  {
   this.messageType = messageType;
   this.messageContent = messageContent;
  }
  public StatusMessageData()
  {
  }
 }

 /// <summary>
 /// 提示消息类别
 /// </summary>
 public enum StatusMessageType
 {
  /// <summary>
  /// 成功
  /// </summary>
  Success = 1,

  /// <summary>
  /// 错误
  /// </summary>
  Error = -1,

  /// <summary>
  /// 提示信息
  /// </summary>
  Hint = 0,
  /// <summary>
  /// 提醒登录
  /// </summary>
  Login = 5,
  /// <summary>
  /// 提示重定向
  /// </summary>
  Redirect = 6,
 }

[HttpPost]
  public ActionResult ExportExcel(SearchModel model)
  {
   
   
   StatusMessageData result = new StatusMessageData();
   if (model.Data == null || model.Data.Count <= 0)
   {
    result.MessageType = StatusMessageType.Error;
    result.MessageContent = "没有要下载的数据";
    return Json(result);
   }
   string fileglobal = "";
   //组织Excel表格
   StringBuilder sb = new StringBuilder(400);
   sb.Append("<table cellspacing='0' rules='all' border='1'>");
   sb.Append("<thead>");
   sb.Append("<tr>");
   sb.Append("<th>列一</th>");
   sb.Append("<th>列二</th>");
   sb.Append("<th>列三</th>");
   sb.Append("<th>列四</th>");
   sb.Append("</tr>");
   sb.Append("</thead>");
   sb.Append("<tbody>");
   try
   {
      foreach (var item in model.Data)
      {
       sb.Append("<tr>");
       sb.Append("<td>");
       sb.Append(item.column1);
       sb.Append("</td>");
       sb.Append("<td>");
       sb.Append(item.column2);
       sb.Append("</td>");
       sb.Append("<td>");
       sb.Append(item.column3);
       sb.Append("</td>");
       sb.Append("<td>");
       sb.Append(item.column4);
       sb.Append("</td>");
       sb.Append("</tr>");
       
      }
    }
   
    sb.Append("</tbody>");
    sb.Append("</table>");
    //以UTF8格式写入文件
    byte[] contentBytes = Encoding.UTF8.GetBytes(sb.ToString());

    string rootDirServerPath = "将生成的文件保存在指定的目录名称";
    //由于我们项目上下载Excel文件基本没有并发的情况，所以只用年月日时分秒来命名文件就可以避免生成相同文件名文件的问题。
    string fileSaveName = "下载的文件名称_" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xls";

    string rootDirServerPhysicPath = Server.MapPath("~" + rootDirServerPath);
    if (!Directory.Exists(rootDirServerPhysicPath))
    {
     Directory.CreateDirectory(rootDirServerPhysicPath);
    }
    string[] strFiles = Directory.GetFiles(rootDirServerPhysicPath);
    if (strFiles.Length > 0)
    {
     foreach (string strFile in strFiles)
     {
      System.IO.File.Delete(strFile);
     }
    }
    //以下是将文件保存到指定目录
    string userFailedSummaryFileSavePath = rootDirServerPhysicPath + "/" + fileSaveName;
    if (System.IO.File.Exists(userFailedSummaryFileSavePath))
    {
     System.IO.File.Delete(userFailedSummaryFileSavePath);
    }
    System.IO.File.WriteAllBytes(userFailedSummaryFileSavePath, contentBytes);
    //拼装好要下载文件的全路径。
    fileglobal = rootDirServerPath + "/" + fileSaveName;
   }
   catch (Exception ex)
   {
    result.MessageType = StatusMessageType.Error;
    result.MessageContent = ex.Message.ToString();
    return Json(result);
   }
   result.MessageType = StatusMessageType.Success;
   result.MessageContent = "正在下载，请稍候...";
   result.Data = fileglobal;
   return Json(result);
  } 

$("#export-excel").click(function (e) {
    e.preventDefault();
    $.post("Controller/ExportExcel.aspx", $("#Form1").serialize(), function (data) {
      art.dialog.tips(data.MessageContent, 1.5, data.MessageType, function () {
        if (data.MessageType == 1) {
          window.open(data.Data);
        } else {
          //错误操作
        }
      });
    });
  });