web用户控件中的gridview怎样实现导出到excel啊
看了很多例子，都没有这方面的介绍，一般页面中可以用rendercontrol实现，在用户控件中总是出错。提示没有放在runat=server，添加了override的那个过程也没用。

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沙发，帮忙顶
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public class JExcel
{
static public void ExportToExcel(DataSet ds, string strTableName, string typeid, string FileName, Page page) //从给定的Dataset和tablename中导出
{

HttpResponse resp;
resp = page.Response;
resp.ContentEncoding = System.Text.Encoding.GetEncoding( "GB2312 ");
resp.AppendHeader( "Content-Disposition ", "attachment;filename= " + FileName);
string colHeaders = " ", ls_item = " ";
int i = 0;

//定义表对象与行对像，同时用DataSet对其值进行初始化
DataTable dt = ds.Tables[strTableName];
DataRow[] myRow = dt.Select( " ");
// typeid== "1 "时导出为EXCEL格式文件；typeid== "2 "时导出为XML格式文件
if (typeid == "excel ")
{
//取得数据表各列标题，各标题之间以\t分割，最后一个列标题后加回车符
for (i = 0; i < dt.Columns.Count - 2; i++)
colHeaders += dt.Columns[i].Caption.ToString() + "\t ";
colHeaders += dt.Columns[i].Caption.ToString() + "\n ";
//向HTTP输出流中写入取得的数据信息
resp.Write(colHeaders);
//逐行处理数据
foreach (DataRow row in myRow)
{
//在当前行中，逐列获得数据，数据之间以\t分割，结束时加回车符\n
for (i = 0; i < dt.Columns.Count - 2; i++)
ls_item += row[i].ToString() + "\t ";
ls_item += row[i].ToString() + "\n ";
//当前行数据写入HTTP输出流，并且置空ls_item以便下行数据
resp.Write(ls_item);
ls_item = " ";
}
}
else
{
if (typeid == "xml ")
{
//从DataSet中直接导出XML数据并且写到HTTP输出流中
resp.Write(ds.GetXml());
}
}
//写缓冲区中的数据到HTTP头文件中
resp.End();
}
static public void ExportToExcel(System.Web.UI.Control ctl) //从DataGrid中导出
{
HttpContext.Current.Response.AppendHeader( "Content-Disposition ", "attachment;filename=Excel.xls ");
HttpContext.Current.Response.Charset = "UTF-8 ";
HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default;
HttpContext.Current.Response.ContentType = "application/ms-excel ";//image/JPEG;text/HTML;image/GIF;vnd.ms-excel/msword
ctl.Page.EnableViewState = false;
System.IO.StringWriter tw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
ctl.RenderControl(hw);
HttpContext.Current.Response.Write(tw.ToString());
HttpContext.Current.Response.End();
}
}
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调用
protected void ImgBtnExport_Click(object sender, ImageClickEventArgs e)
{

SqlConnection conn = new SqlConnection(JDBGeneral.SqlDb.ConnMainString);
SqlDataAdapter adp = new SqlDataAdapter();
adp.TableMappings.Add( "Table ", "sj_jx_sjjf ");
conn.Open();
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandType = CommandType.Text;
comm.CommandText = BuildSqlStr() + " where " + Session[ "strWhere "];
adp.SelectCommand = comm;
DataSet ds =