C# create/modify/read .xlsx files

Question

I am looking for a way to create, modify, read .xlsx files in C# without installing Excel or creating files on the server before giving to the user to download.

I found NPOI http://npoi.codeplex.com/ which looks great but supports .xls not .xlsx

I found ExcelPackage http://excelpackage.codeplex.com/ which looks great but has the additional overhead of creating the file on the server before it can be sent to the user. Does anyone know of a way around this?

I found EPPlus http://epplus.codeplex.com but I am not not certain if this requires creation of a file on the server before it can be sent to the user?

I am pretty new to this so any guidance/examples etc., would be very much appreciated.

Answer 1

With EPPlus it's not required to create file, you can do all with streams, here is an example of ASP.NET ashx handler that will export datatable into excel file and serve it back to the client :

  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;
    }
  }