Reading Excel files from C#

Question

Is there a free or open source library to read Excel files (.xls) directly from a C# program?

It does not need to be too fancy, just to select a worksheet and read the data as strings. So far, I've been using Export to Unicode text function of Excel, and parsing the resulting (tab-delimited) file, but I'd like to eliminate the manual step.

Answer 1

you could write an excel spreadsheet that loads a given excel spreadsheet and saves it as csv (rather than doing it manually).

then you could automate that from c#.

and once its in csv, the c# program can grok that.

(also, if someone asks you to program in excel, it's best to pretend you don't know how)

(edit: ah yes, rob and ryan are both right)

Answer 2

I know that people have been making an Excel "extension" for this purpose.
You more or less make a button in Excel that says "Export to Program X", and then export and send off the data in a format the program can read.

http://msdn.microsoft.com/en-us/library/ms186213.aspx should be a good place to start.

Good luck

Answer 3

Forgive me if I am off-base here, but isn't this what the Office PIA's are for?

Answer 4

If it is just simple data contained in the Excel file you can read the data via ADO.NET. See the connection strings listed here:

http://www.connectionstrings.com/?carrier=excel2007 or http://www.connectionstrings.com/?carrier=excel

-Ryan

Update: then you can just read the worksheet via something like select * from [Sheet1$]

Answer 5

Not free, but with the latest Office there's a very nice automation .Net API. (there has been an API for a long while but was nasty COM) You can do everything you want / need in code all while the Office app remains a hidden background process.

Answer 6

Just did a quick demo project that required managing some excel files. The .NET component from GemBox software was adequate for my needs. It has a free version with a few limitations.

http://www.gemboxsoftware.com/GBSpreadsheet.htm

Answer 7

Here's some code I wrote in C# using .NET 1.1 a few years ago. Not sure if this would be exactly what you need (and may not be my best code :)).

using System;
using System.Data;
using System.Data.OleDb;

namespace ExportExcelToAccess
{
    /// <summary>
    /// Summary description for ExcelHelper.
    /// </summary>
    public sealed class ExcelHelper
    {
     private const string CONNECTION_STRING = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=<FILENAME>;Extended Properties=\"Excel 8.0;HDR=Yes;\";";

     public static DataTable GetDataTableFromExcelFile(string fullFileName, ref string sheetName)
     {
      OleDbConnection objConnection = new OleDbConnection();
      objConnection = new OleDbConnection(CONNECTION_STRING.Replace("<FILENAME>", fullFileName));
      DataSet dsImport = new DataSet();

      try
      {
       objConnection.Open();

       DataTable dtSchema = objConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);

       if( (null == dtSchema) || ( dtSchema.Rows.Count <= 0 ) )
       {
        //raise exception if needed
       }

       if( (null != sheetName) && (0 != sheetName.Length))
       {
        if( !CheckIfSheetNameExists(sheetName, dtSchema) )
        {
         //raise exception if needed
        }
       }
       else
       {
        //Reading the first sheet name from the Excel file.
        sheetName = dtSchema.Rows[0]["TABLE_NAME"].ToString();
       }

       new OleDbDataAdapter("SELECT * FROM [" + sheetName + "]", objConnection ).Fill(dsImport);
      }
      catch (Exception)
      {
       //raise exception if needed
      }
      finally
      {
       // Clean up.
       if(objConnection != null)
       {
        objConnection.Close();
        objConnection.Dispose();
       }
      }


      return dsImport.Tables[0];
      #region Commented code for importing data from CSV file.
      //    string strConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +"Data Source=" + System.IO.Path.GetDirectoryName(fullFileName) +";" +"Extended Properties=\"Text;HDR=YES;FMT=Delimited\"";
      //
      //    System.Data.OleDb.OleDbConnection conText = new System.Data.OleDb.OleDbConnection(strConnectionString);
      //    new System.Data.OleDb.OleDbDataAdapter("SELECT * FROM " + System.IO.Path.GetFileName(fullFileName).Replace(".", "#"), conText).Fill(dsImport);
      //    return dsImport.Tables[0];

      #endregion
     }

     /// <summary>
     /// This method checks if the user entered sheetName exists in the Schema Table
     /// </summary>
     /// <param name="sheetName">Sheet name to be verified</param>
     /// <param name="dtSchema">schema table </param>
     private static bool CheckIfSheetNameExists(string sheetName, DataTable dtSchema)
     {
      foreach(DataRow dataRow in dtSchema.Rows)
      {
       if( sheetName == dataRow["TABLE_NAME"].ToString() )
       {
        return true;
       } 
      }
      return false;
     }
    }
}

Answer 8

var fileName = string.Format("{0}\\fileNameHere", Directory.GetCurrentDirectory());
var connectionString = string.Format("Provider=Microsoft.Jet.OLEDB.4.0; data source={0}; Extended Properties=Excel 8.0;", fileName);

var adapter = new OleDbDataAdapter("SELECT * FROM [workSheetNameHere$]", connectionString);
var ds = new DataSet();

adapter.Fill(ds, "anyNameHere");

DataTable data = ds.Tables["anyNameHere"];

This is what I usually use. It is a little different because I usually stick a AsEnumerable() at the edit of the tables:

var data = ds.Tables["anyNameHere"].AsEnumerable();

as this lets me use LINQ to search and build structs from the fields.

var query = data.Where(x => x.Field<string>("phoneNumber") != string.Empty).Select(x =>
       new MyContact
        {
         firstName= x.Field<string>("First Name"),
         lastName = x.Field<string>("Last Name"),
         phoneNumber =x.Field<string>("Phone Number"),
        });

Answer 9

The ADO.NET approach is quick and easy, but it has a few quirks which you should be aware of, especially regarding how DataTypes are handled.

This excellent article will help you avoid some common pitfalls: http://blog.lab49.com/archives/196

Answer 10

I did a lot of reading from Excel files in C# a while ago, and we used two approaches:

• The COM API, where you access Excel's objects directly and manipulate them through methods and properties
• The ODBC driver that allows to use Excel like a database.

The latter approach was much faster: reading a big table with 20 columns and 200 lines would take 30 seconds via COM, and half a second via ODBC. So I would recommend the database approach if all you need is the data.

Cheers,

Carl

Answer 11

While you did specifically ask for .xls, implying the older file formats, for the OpenXML formats (e.g. xlsx) I highly recommend the OpenXML SDK (http://msdn.microsoft.com/en-us/library/bb448854.aspx)

Answer 12

I recommend the FileHelpers Library which is a free and easy to use .NET library to import/export data from EXCEL, fixed length or delimited records in files, strings or streams + More.

The Excel Data Link Documentation Section http://filehelpers.sourceforge.net/example_exceldatalink.html

Answer 13

Lately, partly to get better at LINQ.... I've been using Excel's automation API to save the file as XML Spreadsheet and then get process that file using LINQ to XML.

Answer 14

This is what I used for Excel 2003:

Dictionary<string, string> props = new Dictionary<string, string>();
props["Provider"] = "Microsoft.Jet.OLEDB.4.0";
props["Data Source"] = repFile;
props["Extended Properties"] = "Excel 8.0";

StringBuilder sb = new StringBuilder();
foreach (KeyValuePair<string, string> prop in props)
{
    sb.Append(prop.Key);
    sb.Append('=');
    sb.Append(prop.Value);
    sb.Append(';');
}
string properties = sb.ToString();

using (OleDbConnection conn = new OleDbConnection(properties))
{
    conn.Open();
    DataSet ds = new DataSet();
    string columns = String.Join(",", columnNames.ToArray());
    using (OleDbDataAdapter da = new OleDbDataAdapter(
        "SELECT " + columns + " FROM [" + worksheet + "$]", conn))
    {
        DataTable dt = new DataTable(tableName);
        da.Fill(dt);
        ds.Tables.Add(dt);
    }
}

Answer 15

Koogra is an open-source component written in C# that reads and writes Excel files.

Answer 16

SpreadsheetGear for .NET is an Excel compatible spreadsheet component for .NET. You can see what our customers say about performance on the right hand side of our product page. You can try it yourself with the free, fully-functional evaluation.

Answer 17

ExcelMapper is an open source tool (http://code.google.com/p/excelmapper/) that can be used to read Excel worksheets as Strongly Typed Objects. It supports both xls and xlsx formats.

Answer 18

I just used ExcelLibrary to load an .xls spreadsheet into a DataSet. Worked great for me.

Answer 19

SmartXLS is another excel spreadsheet component which support most features of excel Charts,formulas engines, and can read/write the excel2007 openxml format.

Answer 20

Excel Package is an open-source (GPL) component for reading/writing Excel 2007 files. I used it on a small project, and the API is straightforward. Works with XLSX only (Excel 200&), not with XLS.

The source code also seems well-organized and easy to get around (if you need to expand functionality or fix minor issues as I did).

At first, I tried the ADO.Net (Excel connection string) approach, but it was fraught with nasty hacks -- for instance if second row contains a number, it will return ints for all fields in the column below and quietly drop any data that doesn't fit.

Answer 21

You could try GemBox.Spreadsheet .NET Component for reading and writing Excel files in variety of formats like XLS, XLSX, ODS, CSV, HTML.

It is very fast and easy to use.

Free version is limited to maximum 150 rows per sheet and 5 sheets per workbook, but you can use it in your commercial applications.

Answer 22

You can try using this open source solution that makes dealing with Excel a lot more cleaner.

http://excelwrapperdotnet.codeplex.com/

Answer 23

Try to use Spire.XLS (http://www.e-iceblue.com/Introduce/excel-for-net-introduce.html)

to read and write excel file so easy, I use from last year, quit good.

Answer 24

If you need fast make something then better to process xls by hand. I made short article on it with example: Excel sheet processing

Answer 25

Here is the simple perhaps useful solution http://chetanwarade.wordpress.com/2010/08/18/read-excel-with-ado-net/

Answer 26

SpreadsheetGear is awesome. Yes it's an expense, but compared to twiddling with these other solutions, it's worth the cost. It is fast, reliable, very comprehensive, and I have to say after using this product in my fulltime software job for over a year and a half, their customer support is fantastic!

Answer 27

How about Excel Data Reader?

http://exceldatareader.codeplex.com/

I've used in it anger, in a production environment, to pull large amounts of data from a variety of Excel files into SQL Server Compact. It works very well and it's rather robust.