传入一个table，文件名，导出Excel的方法

/// <summary>
/// 将DataTable 导出为EXCEL，并直接提供下载
/// </summary>
/// <param name="ds">需要导处的DataTable</param>
/// <param name="fileName">到处生成的文件名</param>
///
public bool ExportExcelByDataTable(DataTable dt, string fileName)
{

try
{
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.Charset = "utf-7";
HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-7");

HttpContext.Current.Response.ContentType = "application/vnd.ms-excel";
StringWriter stringWrite = new StringWriter();
HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);
DataGrid dg = new DataGrid();
dg.HeaderStyle.CssClass = "dgHead";
dg.DataSource = dt;
dg.DataBind();
dg.RenderControl(htmlWrite);

HttpContext.Current.Response.Write(stringWrite.ToString());
HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8) + ".xls");
HttpContext.Current.Response.Charset = "gb2312";
HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
HttpContext.Current.Response.End();
return true;
}
catch
{
return false;
}
}