asp.net 有什么步骤把导出的excel数据 行变成列 列变成行

/// <summary> 
    /// 将DataTable数据导出到EXCEL，调用该方法后自动返回可下载的文件流 
    /// </summary> 
    /// <param name="dtData">要导出的数据源</param> 
    public static void DataTable1Excel(System.Data.DataTable dtData)
    {
        System.Web.UI.WebControls.GridView gvExport = null;
        // 当前对话 
        System.Web.HttpContext curContext = System.Web.HttpContext.Current;
        // IO用于导出并返回excel文件 
        System.IO.StringWriter strWriter = null;
        System.Web.UI.HtmlTextWriter htmlWriter = null;

        if (dtData != null)
        {
            // 设置编码和附件格式 
            curContext.Response.ContentType = "application/vnd.ms-excel";
            curContext.Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
            curContext.Response.Charset = "utf-8";

            // 导出excel文件 
            strWriter = new System.IO.StringWriter();
            htmlWriter = new System.Web.UI.HtmlTextWriter(strWriter);
            // 为了解决gvData中可能进行了分页的情况，需要重新定义一个无分页的GridView 
            gvExport = new System.Web.UI.WebControls.GridView();
            gvExport.DataSource = dtData.DefaultView;
            gvExport.AllowPaging = false;
            gvExport.DataBind();

            // 返回客户端 
            gvExport.RenderControl(htmlWriter);
            curContext.Response.Write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=gb2312\" />" + strWriter.ToString());
            curContext.Response.End();
        }
    }