如何用StreamWriter把一个DataTable里面的东西写到client

目前是把datatable里面的数据整理成一个string,但是streamwriter会把string写到server上，
如何把它直接写到client端呢？
用下面这种方法是可以把数据下载到client但是，xls里面会有乱码，用streamwriter就不会有
Response.Clear();
Response.Charset = "UTF-8";
Response.AddHeader("Content-Disposition","attachment; filename=Data.xls");
Response.ContentType = "application/vnd.ms-excel";
Response.ContentEncoding = Encoding.UTF8;
StringWriter stringWrite = new StringWriter("");
HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);
DataGrid dg = new DataGrid();
dg.DataSource = dt;
dg.DataBind();
dg.RenderControl(htmlWrite);
Response.Write(stringWrite.ToString());
Response.End();