使用EPPlus，不需要创建文件，您可以使用流来完成所有操作，这是一个ASP.NET
ashx处理程序的示例，该处理程序会将数据表导出到excel文件中并将其提供给客户端：

  public class GetExcel : IHttpHandler
  {
    public void ProcessRequest(HttpContext context)
    {
      var dt = DBServer.GetDataTable("select * from table");
      var ms = GetExcel.DataTableToExcelXlsx(dt, "Sheet1");
      ms.WriteTo(context.Response.OutputStream);
      context.Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
      context.Response.AddHeader("Content-Disposition", "attachment;filename=EasyEditCmsGridData.xlsx");
      context.Response.StatusCode = 200;
      context.Response.End();   
    }

    public bool IsReusable
    {
      get
      {
        return false;
      }
    }

    public static MemoryStream DataTableToExcelXlsx(DataTable table, string sheetName)
    {
      var result = new MemoryStream();
      var pack = new ExcelPackage();
      var ws = pack.Workbook.Worksheets.Add(sheetName);

      int col = 1;
      int row = 1;
      foreach (DataRow rw in table.Rows)
      {
        foreach (DataColumn cl in table.Columns)
        {
          if (rw[cl.ColumnName] != DBNull.Value)
            ws.Cells[row, col].Value = rw[cl.ColumnName].ToString();
          col++;
        }
        row++;
        col = 1;
      }
      pack.SaveAs(result);
      return result;
    }
  }