asp.net 导出Excel时，解决纯数字字符串变成类似这样的 2.00908E+18 形式的代码

1.当导入excel的数据字段有 [24928161122003E8]，导入excel后会以科学计数法转换成2.4928161122003E21也就是2.49*10的21次方，这时候需要转换一下格式.

public override void VerifyRenderingInServerForm(Control control)
{
}
protected void btnexcel_Click(object sender, EventArgs e)
{
foreach (GridViewRow dg in this.gvItem.Rows)
{
dg.Cells[10].Attributes.Add("style", "vnd.ms-excel.numberformat: @;");//第十一列的字段是[24928161122003E8]需要转换格式.
}

Response.Clear();
Response.Buffer = true;
Response.Charset = "GB2312";
Response.AppendHeader("Content-Disposition", "attachment;filename=Message.xls");
Response.ContentEncoding = System.Text.Encoding.UTF8;
Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
System.IO.StringWriter oStringWriter = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
this.gvItem.RenderControl(oHtmlTextWriter);
Response.Output.Write(oStringWriter.ToString());
Response.Flush();
Response.End();
}