public void NpoiExcel(DataTable dt, string title)
{
  NPOI.HSSF.UserModel.HSSFWorkbook book = new NPOI.HSSF.UserModel.HSSFWorkbook();
  NPOI.SS.UserModel.ISheet sheet = book.CreateSheet("Sheet1");

  NPOI.SS.UserModel.IRow headerrow = sheet.CreateRow(0);
  ICellStyle style = book.CreateCellStyle();
  style.Alignment = HorizontalAlignment.Center;
  style.VerticalAlignment = VerticalAlignment.Center;

  for (int i = 0; i < dt.Columns.Count; i++)
  {
 ICell cell = headerrow.CreateCell(i);
 cell.CellStyle = style;
 cell.SetCellValue(dt.Columns[i].ColumnName);

  }

  MemoryStream ms = new MemoryStream();
  book.Write(ms);
  Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}.xls", HttpUtility.UrlEncode(title + "_" + DateTime.Now.ToString("yyyy-MM-dd"), System.Text.Encoding.UTF8)));
  Response.BinaryWrite(ms.ToArray());
  Response.End();
  book = null;
  ms.Close();
  ms.Dispose();
}

/// <summary>
/// 连接Excel 读取Excel数据  并返回DataSet数据集合
/// </summary>
/// <param name="filepath">Excel服务器路径</param>
/// <param name="tableName">Excel表名称</param>
/// <returns></returns>
public static System.Data.DataSet ExcelSqlConnection(string filepath, string tableName)
{

  string strCon = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + filepath + ";Extended Properties='Excel 8.0;HDR=YES;IMEX=1'";
  OleDbConnection ExcelConn = new OleDbConnection(strCon);
  try
  {
 string strCom = string.Format("SELECT * FROM [Sheet1$]");
 ExcelConn.Open();
 OleDbDataAdapter myCommand = new OleDbDataAdapter(strCom, ExcelConn);
 DataSet ds = new DataSet();
 myCommand.Fill(ds, "[" + tableName + "$]");
 ExcelConn.Close();
 return ds;
  }
  catch
  {
 ExcelConn.Close();
 return null;
  }
}