把WebForm数据导出到Excel中

上午给系统的订单管理部分添加了一个功能，把查询到的订单信息导出到Excel，供管理员分析用。以前写的代码如下：

Response.Clear();
Response.BufferOutput = true;
Response.Charset = "GB2312";
Response.AppendHeader("Content-Disposition","attachment;filename = FileName.xls");
Response.ContentEncoding = Encoding.GetEncoding("GB2312");
Response.ContentType = "application/ms-excel";
this.EnableViewState = false;
System.Globalization.CultureInfo myinfo = new System.Globalization.CultureInfo("ZH-CN", true);
StringWriter osw = new StringWriter(myinfo);
HtmlTextWriter ohtw = new HtmlTextWriter(osw);
dgQueryResult.RenderControl(ohtw);
Response.Write(osw);
Response.End(); 
        我的查询用了分页，客户要求把所有查询到的数据都导出到Excel，所以不能象以前那样通过把控件的内容导出到Excel来实现此功能，于是把代码改成这样：
   Response.Clear();
Response.BufferOutput = true;
Response.Charset = "GB2312";
Response.AppendHeader("Content-Disposition","attachment;filename = 订单.xls");
Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
Response.ContentType = "application/ms-excel";
string strExcelHeader = string.Empty;
string strExcelItems;
if(ViewState["SQL"] != null)    // 取前面查询用的SQL语句
{
     // 取得各列标题，各标题之间以t分割，最后一个列标题后加回车符 
     strExcelHeader = "订单号t经销商t地区t小类t商品t实付金额t下单时间t有效状态t处理状态tn";                                     
    // 向HTTP输出流中写入取得的数据信息 
    Response.Write(strExcelHeader);   
         
    // 逐行处理查询结果数据 
    ITDBHandle itDbHandle = new ITDBHandle();
    itDbHandle.QueryString = ViewState["SQL"].ToString();
    SqlDataReader reader = itDbHandle.ExecuteDataReader();      
    while(reader.Read()) 
    { 
        strExcelItems = string.Empty;
        strExcelItems += reader["OrderID"].ToString() + "t";   
        strExcelItems += reader["DealerName"].ToString() + "t";
        strExcelItems += reader["City"].ToString() + "t";
        strExcelItems += reader["SmallClassName"].ToString() + "t";
        strExcelItems += reader["BrandName"].ToString() + reader["Model"].ToString() + "t";
        strExcelItems += reader["TotalPrice"].ToString() + "t";
        strExcelItems += reader["OrderDate"].ToString() + "t";
        strExcelItems += reader["IsValid"].ToString() + "t";
        strExcelItems += reader["DealState"].ToString()  +"n";                                                  
        Response.Write(strExcelItems); 
   } 
    reader.Close();
    Response.End();
}   
       我这里只是简单的把查询到的数据以Excel的形式Write出来(当然也可以是其他格式，比如XML)，对简单的需求足矣了，当然，用.NET直接去操作Excel文件也是很简单的，有很多这样的例子可以参考。