NpoiExport

public static void Export(HttpResponse httpResponse, IWorkbook workBook, string fileName)
{
    httpResponse.Clear();
    MemoryStream ms = new MemoryStream();
    workBook.Write(ms);
    if (fileName.ToLower().EndsWith(".xls"))
        httpResponse.ContentType = "application/vnd.ms-excel";
    else if (fileName.ToLower().EndsWith(".xlsx"))
        httpResponse.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
    else
        throw new Exception("未知的檔案格式");
    httpResponse.AddHeader("content-disposition", "attachment; filename=" + fileName);
    httpResponse.BinaryWrite(ms.ToArray());
    httpResponse.Flush();
    httpResponse.End();
    workBook = null;
    ms.Close();
    ms.Dispose();
}