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Generate Excel files without using Microsoft Excel

, 22 Jun 2011 CPOL
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A C# class to create Excel files without requiring Microsoft Excel.


Generating Excel files from web pages or other applications is a major subject in many articles. I'd like to present here a solution that does not require MS Excel to be installed on the target computer. This article shows how to create Microsoft Excel Binary Interchange File Format (BIFF) without using Microsoft Excel. BIFF is the native file format for Excel data, and can be viewed and modified in Microsoft Excel 97 or later.

Approaches and problems

The technique that is most frequently used to transfer data to an Excel workbooks is Automation. With Automation, you can call methods and properties that are specific to Excel tasks, but this solution has many drawbacks. Some of them are described in the Microsoft Knowledge Base. Additionally, you have to manage the lifetime of the temporary XLS files created on the server. Also, it is slow, because Excel runs in a separate process.

ExcelWriter class

The solution presented here is to write directly to a stream in Excel binary file format. For this purpose, I created very small C# class called ExcelWriter.

ExcelWriter class diagram
/// <summary>
/// Produces Excel file without using Excel
/// </summary>
public class ExcelWriter
    private Stream stream;
    private BinaryWriter writer;

    private ushort[] clBegin = { 0x0809, 8, 0, 0x10, 0, 0 };
    private ushort[] clEnd = { 0x0A, 00 };

    private void WriteUshortArray(ushort[] value)
        for (int i = 0; i < value.Length; i++)

    /// <summary>
    /// Initializes a new instance of the <see cref="ExcelWriter"/> class.
    /// </summary>
    /// <param name="stream">The stream.</param>
    public ExcelWriter(Stream stream)
    { = stream;
        writer = new BinaryWriter(stream);

    /// <summary>
    /// Writes the text cell value.
    /// </summary>
    /// <param name="row">The row.</param>
    /// <param name="col">The col.</param>
    /// <param name="value">The string value.</param>
    public void WriteCell(int row, int col, string value)
        ushort[] clData = { 0x0204, 0, 0, 0, 0, 0 };
        int iLen = value.Length;
        byte[] plainText = Encoding.ASCII.GetBytes(value);
        clData[1] = (ushort)(8 + iLen);
        clData[2] = (ushort)row;
        clData[3] = (ushort)col;
        clData[5] = (ushort)iLen;

    /// <summary>
    /// Writes the integer cell value.
    /// </summary>
    /// <param name="row">The row number.</param>
    /// <param name="col">The column number.</param>
    /// <param name="value">The value.</param>
    public void WriteCell(int row, int col, int value)
        ushort[] clData = { 0x027E, 10, 0, 0, 0 };
        clData[2] = (ushort)row;
        clData[3] = (ushort)col;
        int iValue = (value << 2) | 2;

    /// <summary>
    /// Writes the double cell value.
    /// </summary>
    /// <param name="row">The row number.</param>
    /// <param name="col">The column number.</param>
    /// <param name="value">The value.</param>
    public void WriteCell(int row, int col, double value)
        ushort[] clData = { 0x0203, 14, 0, 0, 0 };
        clData[2] = (ushort)row;
        clData[3] = (ushort)col;

    /// <summary>
    /// Writes the empty cell.
    /// </summary>
    /// <param name="row">The row number.</param>
    /// <param name="col">The column number.</param>
    public void WriteCell(int row, int col)
        ushort[] clData = { 0x0201, 6, 0, 0, 0x17 };
        clData[2] = (ushort)row;
        clData[3] = (ushort)col;

    /// <summary>
    /// Must be called once for creating XLS file header
    /// </summary>
    public void BeginWrite()

    /// <summary>
    /// Ends the writing operation, but do not close the stream
    /// </summary>
    public void EndWrite()

Using the code

The ExcelWriter sample is a console application that writes an XLS file to the name and location specified. The XLS file that is created is simply an empty spreadsheet. Then, you can start to write cell values by calling the WriteCell method with the row number, column number, and a cell value as parameters:

namespace XLSExportDemo
    class Program
        static void Main(string[] args)
            FileStream stream = new FileStream("demo.xls", FileMode.OpenOrCreate);
            ExcelWriter writer = new ExcelWriter(stream);
            writer.WriteCell(0, 0, "ExcelWriter Demo");
            writer.WriteCell(1, 0, "int");
            writer.WriteCell(1, 1, 10);
            writer.WriteCell(2, 0, "double");
            writer.WriteCell(2, 1, 1.5);
            writer.WriteCell(3, 0, "empty");
            writer.WriteCell(3, 1);

The picture below shows the final result of this sample:

The ExcelWriter class supports numeric and text values for the cells, and can be used for exporting data from the database to an XLS file, or for producing an XLS stream from a website on the fly.

I hope this article gives you a head start in working with Excel files from .NET and C#.


  • 03 March 2009 - Initial submission.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Serhiy Perevoznyk
Belgium Belgium
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Comments and Discussions

GeneralGenerate Excel files without using Microsoft Excel Pin
vishnus790, 16-Mar-15 8:26
membervishnus79016-Mar-15 8:26 
QuestionHow to Parse excel Formula or What is mean by "Parsed expression" in Formula Cell Pin
Member 11426223, 5-Feb-15 22:35
memberMember 114262235-Feb-15 22:35 
QuestionWriting Unicode Pin
Member 11072271, 10-Sep-14 3:43
memberMember 1107227110-Sep-14 3:43 
Question[My vote of 1] Completely Worthless Pin
MSDEVTECHNIK, 28-Aug-14 10:56
memberMSDEVTECHNIK28-Aug-14 10:56 
QuestionSee also this: Pin
Dietmar Schoder, 29-Jul-14 6:26
professionalDietmar Schoder29-Jul-14 6:26 
Questionis anyone still develop this way? Pin
bonjot, 5-Jul-14 21:41
memberbonjot5-Jul-14 21:41 
QuestionExcel row Limit Pin
csharpi, 16-May-14 10:58
membercsharpi16-May-14 10:58 
QuestionAttach ExcelDocument to Email Pin
vaughantrebilco, 10-Apr-14 13:46
membervaughantrebilco10-Apr-14 13:46 
GeneralPerfect Class Pin
William Costa Rodrigues, 19-Feb-14 13:22
memberWilliam Costa Rodrigues19-Feb-14 13:22 
Questionexcel cannot open the file .xlsx because the file format Pin
bellona888, 10-Feb-14 22:43
memberbellona88810-Feb-14 22:43 
QuestionSpecial Characters Problem Pin
Emre Can Serteli, 7-Dec-13 6:14
memberEmre Can Serteli7-Dec-13 6:14 
AnswerRe: Special Characters Problem Pin
Member 10585247, 14-Jul-14 0:33
memberMember 1058524714-Jul-14 0:33 
QuestionHow to avoid protected view? Pin
Amit Ghorai, 24-Aug-13 6:04
memberAmit Ghorai24-Aug-13 6:04 
Questionhow to create a new worksheet in the same document Pin
Member 10221967, 20-Aug-13 20:55
memberMember 1022196720-Aug-13 20:55 
AnswerRe: how to create a new worksheet in the same document Pin
Javier Chan, 26-Feb-15 19:48
memberJavier Chan26-Feb-15 19:48 
QuestionMy Vote of 5! Pin
jiaxing yee, 6-Jun-13 15:45
memberjiaxing yee6-Jun-13 15:45 
GeneralMy vote of 5 Pin
hygoh, 30-May-13 17:28
memberhygoh30-May-13 17:28 
Generalvery cool stuff Pin
Jerry13, 9-May-13 3:31
memberJerry139-May-13 3:31 
QuestionI can't open the generated XLS file through Excel 2010 Pin
Josen.L.Zhang, 9-Apr-13 1:03
memberJosen.L.Zhang9-Apr-13 1:03 
AnswerRe: I can't open the generated XLS file through Excel 2010 Pin
sangheraajit, 14-Apr-13 23:04
membersangheraajit14-Apr-13 23:04 
GeneralMy vote of 5 Pin
DineshMaind, 5-Mar-13 7:01
memberDineshMaind5-Mar-13 7:01 
QuestionPlease add Border Style at next upgrade Pin
phong1040572, 24-Jan-13 17:29
memberphong104057224-Jan-13 17:29 
SuggestionColumn Width AutoFit? Pin
adriancs, 9-Jan-13 15:46
mvpadriancs9-Jan-13 15:46 
SuggestionCode Patch, Write DataTable [modified] Pin
adriancs, 9-Jan-13 15:01
mvpadriancs9-Jan-13 15:01 
QuestionIs it possible to Write stream to respose headers instead of a demo.xls file? Pin
shabari7, 13-Dec-12 1:25
membershabari713-Dec-12 1:25 

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