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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

QuestionSpecial Characters Problem PinmemberEmre Can Serteli7-Dec-13 6:14 
AnswerRe: Special Characters Problem PinmemberMember 1058524714-Jul-14 0:33 
QuestionHow to avoid protected view? PinmemberAmit Ghorai24-Aug-13 6:04 
Questionhow to create a new worksheet in the same document PinmemberMember 1022196720-Aug-13 20:55 
AnswerRe: how to create a new worksheet in the same document PinmemberJavier Chan26-Feb-15 19:48 
QuestionMy Vote of 5! Pinmemberjiaxing yee6-Jun-13 15:45 
GeneralMy vote of 5 Pinmemberhygoh30-May-13 17:28 
Generalvery cool stuff PinmemberJerry139-May-13 3:31 
QuestionI can't open the generated XLS file through Excel 2010 PinmemberJosen.L.Zhang9-Apr-13 1:03 
AnswerRe: I can't open the generated XLS file through Excel 2010 Pinmembersangheraajit14-Apr-13 23:04 
GeneralMy vote of 5 PinmemberDineshMaind5-Mar-13 7:01 
QuestionPlease add Border Style at next upgrade Pinmemberphong104057224-Jan-13 17:29 
SuggestionColumn Width AutoFit? Pinmvpadriancs9-Jan-13 15:46 
SuggestionCode Patch, Write DataTable [modified] Pinmvpadriancs9-Jan-13 15:01 
QuestionIs it possible to Write stream to respose headers instead of a demo.xls file? Pinmembershabari713-Dec-12 1:25 
QuestionMore feature rich alternative PinmemberAndrew Kirillov11-Nov-12 23:30 
AnswerRe: More feature rich alternative PinmemberMember 940799029-Mar-13 17:58 
QuestionMultiple Sheets PinmemberMember 810781128-Oct-12 17:09 
Questionlimited to 255 chars per cell. how we can increase the limit ..? Pinmemberaisoft19-Oct-12 6:50 
QuestionGenerating Excel Pinmembernirajzambad7-Aug-12 4:03 
What if i dont want to create new instance of excel sheet and write to the previous excel file
and to the next row where i stopped last time
GeneralMy vote of 5 PinmemberHuỳnh Hữu Ân24-Jul-12 19:06 
QuestionThe generated xls file could not be read by OLEDB Pinmemberdaiwuju4-Jul-12 23:57 
QuestionA minor problem in Chinese Font Pinmemberdaiwuju29-Jun-12 20:05 
AnswerRe: A minor problem in Chinese Font PinmemberMember 1087982114-Sep-14 23:49 
QuestionMere cells Pinmemberdaniloao31-May-12 14:50 
QuestionBorders PinmemberMember 901259929-May-12 7:49 
QuestionMore Than one WorkSheet Pinmemberhichamveo24-May-12 7:57 
QuestionGreat work!! PinmemberCurtCobrain7-Apr-12 5:57 
GeneralMy vote of 5 PinmemberMikhail Tsennykh (devnoob)19-Mar-12 9:50 
QuestionCreating .XLSX file Pinmemberbhavtosh.sharma2-Mar-12 1:57 
AnswerRe: Creating .XLSX file Pinmemberdaiwuju29-Jun-12 20:00 
AnswerRe: Creating .XLSX file PinmemberConstance R19-Dec-13 0:28 
QuestionProtected View Pinmemberccchg9-Feb-12 1:22 
QuestionSpecial characters are not coming Pinmemberiliyash11-Jan-12 5:37 
AnswerRe: Special characters are not coming Pinmemberiliyash11-Jan-12 21:42 
Questionprint PinmemberMember 85283912-Jan-12 11:17 
QuestionI get an Office File Validation warning PinmemberLeo Muller19-Dec-11 21:27 
GeneralMy vote of 5 PinmemberMember 366623525-Nov-11 1:10 
QuestionHO TO MERGE COLUMS AND ROWS Pinmembersheriefes11-Nov-11 1:08 
Questioninsert image PinmemberJorge Teodoro1-Nov-11 10:08 
QuestionExcel file gives error on opening Pinmembershubhamalhotra17-Oct-11 4:18 
Questionwarrior!that would be perfect if ExcelReader.cs and ExcelSheet is adding to the file Pinmemberbatsword13-Sep-11 17:31 
QuestionMy vote of 5 PinmemberFilip D'haene9-Sep-11 6:58 
QuestionAdding new work sheet would be a great feature in the next version PinmemberNikolay Dovgaluk1-Aug-11 5:06 
QuestionHow to create 2nd Excel sheet using your method? PinmemberMember 399944929-Jul-11 19:50 
AnswerRe: How to create 2nd Excel sheet using your method? PinmemberAA123546548978917-May-12 5:00 
AnswerRe: How to create 2nd Excel sheet using your method? PinmemberKapilDesai28-Aug-12 22:48 
QuestionVery Easy Pinmembertexgfalco30-Jun-11 14:32 
AnswerRe: Very Easy PinmemberSerhiy Perevoznyk1-Jul-11 10:37 
GeneralMy vote of 5 PinmemberJamal Alqabandi28-Jun-11 0:59 

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