protected void btnPrint_Click(object sender, EventArgs e)     {         string strPath = "MFOut" + DateTime.Now.ToString("yyyymmddhhmmssfff") + ".xls";         DataGrid dg = new DataGrid();         dg.DataSource = dtMain;         dg.DataBind();         Response.Clear();         Response.AddHeader("content-disposition", "attachment;filename=" + strPath + "");         Response.Charset = "gb2312";         Response.ContentEncoding = System.Text.Encoding.UTF8;//不设置会有乱码         Response.ContentType = "application/vnd.xls";         System.IO.StringWriter stringWrite = new System.IO.StringWriter();         System.Web.UI.HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);         dg.RenderControl(htmlWrite);         Response.Write(stringWrite.ToString());         Response.End();     }     public override void VerifyRenderingInServerForm(Control control)     {         //这个方法不能删除掉 导出时要用到，不然会报错：         //类型“GridView”的控件“ctl00_ContentPlaceHolder1_GridView1”必须放在具有 runat=server 的窗体标记内     }