.NET Excel Library that can read/write .xls files

I'm looking for an Excel library which reads/writes .xls (not .xlsx) files.

I'm using http://code.google.com/p/excellibrary/">excellibrary</a> but it's very buggy and I http://code.google.com/p/excellibrary/issues/detail?id=60">can't seem to open the files I create. The issue has been known for almost a year and hasn't been fixed yet.

I've seen in another thread someone suggested http://epplus.codeplex.com/">EPPlus</a>;, but that only works with the 2007/2010 .xlsx format.

I've used http://sourceforge.net/projects/koogra/">Koogra</a> in the past, and been quite happy with it, but I believe it can only read... not write.

If you know of a library, please let me know what it's called.

Edit: I'm quite happy to create my Excel file with the built-in Microsoft.Office.Interop.Excel if necessary, however my machine has Office 2007 and the target machines only have Office 2003. I noticed I have 2 file versions for that library: 12, and 14. I checked the Excel version on the target machines and it's 11.8169.8172 - I'm assuming that the built-in Excel interop will not work on the target?

I'd recommend NPOI. NPOI is FREE and works exclusively with .XLS files. It has helped me a lot.

Detail: you don't need to have Microsoft Office installed on your machine to work with .XLS files if you use NPOI.

Check these blog posts:

Creating Excel spreadsheets .XLS and .XLSX in C#

NPOI with Excel Table and dynamic Chart

[UPDATE]

NPOI 2.0 added support for XLSX and DOCX.

You can read more about it here:

NPOI 2.0 series of posts scheduled

Is there a reason why you can't use the Excel ODBC connection to read and write to Excel? For example, I've used the following code to read from an Excel file row by row like a database:

private DataTable LoadExcelData(string fileName)
{
  string Connection = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fileName + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=1\";";

  OleDbConnection con = new OleDbConnection(Connection);

  OleDbCommand command = new OleDbCommand();

  DataTable dt = new DataTable(); OleDbDataAdapter myCommand = new OleDbDataAdapter("select * from [Sheet1$] WHERE LastName <> '' ORDER BY LastName, FirstName", con);

  myCommand.Fill(dt);

  Console.WriteLine(dt.Rows.Count);

  return dt;
}

You can write to the Excel "database" the same way. As you can see, you can select the version number to use so that you can downgrade Excel versions for the machine with Excel 2003. Actually, the same is true for using the Interop. You can use the lower version and it should work with Excel 2003 even though you only have the higher version on your development PC.

You may consider 3rd party tool that called Excel Jetcell .NET component for read/write excel files:

C# sample

// Create New Excel Workbook
ExcelWorkbook Wbook = new ExcelWorkbook();
ExcelCellCollection Cells = Wbook.Worksheets.Add("Sheet1").Cells;

Cells["A1"].Value = "Excel writer example (C#)";
Cells["A1"].Style.Font.Bold = true;
Cells["B1"].Value = "=550 + 5";

// Write Excel XLS file
Wbook.WriteXLS("excel_net.xls");

VB.NET sample

' Create New Excel Workbook
Dim Wbook As ExcelWorkbook = New ExcelWorkbook()
Dim Cells As ExcelCellCollection = Wbook.Worksheets.Add("Sheet1").Cells

Cells("A1").Value = "Excel writer example (C#)"
Cells("A1").Style.Font.Bold = True
Cells("B1").Value = "=550 + 5"

' Write Excel XLS file
Wbook.WriteXLS("excel_net.xls")