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Generate Excel files without using Microsoft Excel

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22 Jun 2011CPOL2 min read 645.1K   24.3K   269   153
A C# class to create Excel files without requiring Microsoft Excel.

Introduction

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
C#
/// <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++)
            writer.Write(value[i]);
    }

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

    /// <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;
        WriteUshortArray(clData);
        int iValue = (value << 2) | 2;
        writer.Write(iValue);
    }

    /// <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;
        WriteUshortArray(clData);
        writer.Write(value);
    }

    /// <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;
        WriteUshortArray(clData);
    }

    /// <summary>
    /// Must be called once for creating XLS file header
    /// </summary>
    public void BeginWrite()
    {
        WriteUshortArray(clBegin);
    }

    /// <summary>
    /// Ends the writing operation, but do not close the stream
    /// </summary>
    public void EndWrite()
    {
        WriteUshortArray(clEnd);
        writer.Flush();
    }
}

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:

C#
namespace XLSExportDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            FileStream stream = new FileStream("demo.xls", FileMode.OpenOrCreate);
            ExcelWriter writer = new ExcelWriter(stream);
            writer.BeginWrite();
            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);
            writer.EndWrite();
            stream.Close();
        }
    }
}

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#.

History

  • 03 March 2009 - Initial submission.

License

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


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Comments and Discussions

 
Questionhow to create a new worksheet in the same document Pin
Member 1022196720-Aug-13 19:55
Member 1022196720-Aug-13 19:55 
AnswerRe: how to create a new worksheet in the same document Pin
Javier Chan26-Feb-15 18:48
Javier Chan26-Feb-15 18:48 
QuestionMy Vote of 5! Pin
jiaxing yee6-Jun-13 14:45
jiaxing yee6-Jun-13 14:45 
GeneralMy vote of 5 Pin
hygoh30-May-13 16:28
hygoh30-May-13 16:28 
Generalvery cool stuff Pin
Jerry139-May-13 2:31
Jerry139-May-13 2:31 
QuestionI can't open the generated XLS file through Excel 2010 Pin
Josen.L.Zhang9-Apr-13 0:03
Josen.L.Zhang9-Apr-13 0:03 
AnswerRe: I can't open the generated XLS file through Excel 2010 Pin
sangheraajit14-Apr-13 22:04
sangheraajit14-Apr-13 22:04 
GeneralMy vote of 5 Pin
DineshMaind5-Mar-13 6:01
DineshMaind5-Mar-13 6:01 
Awesome API...
QuestionPlease add Border Style at next upgrade Pin
phong104057224-Jan-13 16:29
phong104057224-Jan-13 16:29 
SuggestionColumn Width AutoFit? Pin
adriancs9-Jan-13 14:46
mvaadriancs9-Jan-13 14:46 
SuggestionCode Patch, Write DataTable Pin
adriancs9-Jan-13 14:01
mvaadriancs9-Jan-13 14:01 
QuestionIs it possible to Write stream to respose headers instead of a demo.xls file? Pin
PBGuy13-Dec-12 0:25
professionalPBGuy13-Dec-12 0:25 
QuestionMore feature rich alternative Pin
Andrew Kirillov11-Nov-12 22:30
Andrew Kirillov11-Nov-12 22:30 
AnswerRe: More feature rich alternative Pin
Member 940799029-Mar-13 16:58
Member 940799029-Mar-13 16:58 
QuestionMultiple Sheets Pin
Member 810781128-Oct-12 16:09
Member 810781128-Oct-12 16:09 
Questionlimited to 255 chars per cell. how we can increase the limit ..? Pin
ITGeekCoder19-Oct-12 5:50
ITGeekCoder19-Oct-12 5:50 
QuestionGenerating Excel Pin
nirajzambad7-Aug-12 3:03
nirajzambad7-Aug-12 3:03 
GeneralMy vote of 5 Pin
Huỳnh Hữu Ân24-Jul-12 18:06
Huỳnh Hữu Ân24-Jul-12 18:06 
QuestionThe generated xls file could not be read by OLEDB Pin
daiwuju4-Jul-12 22:57
daiwuju4-Jul-12 22:57 
QuestionA minor problem in Chinese Font Pin
daiwuju29-Jun-12 19:05
daiwuju29-Jun-12 19:05 
AnswerRe: A minor problem in Chinese Font Pin
lonely_king14-Sep-14 22:49
lonely_king14-Sep-14 22:49 
QuestionMere cells Pin
daniloao31-May-12 13:50
daniloao31-May-12 13:50 
QuestionBorders Pin
Member 901259929-May-12 6:49
Member 901259929-May-12 6:49 
QuestionMore Than one WorkSheet Pin
hichamveo24-May-12 6:57
hichamveo24-May-12 6:57 
QuestionGreat work!! Pin
CurtCobrain7-Apr-12 4:57
CurtCobrain7-Apr-12 4:57 

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