MeshWeaver.DataSetReader.Excel.OpenXmlFormat 3.0.0-rc6

MeshWeaver.DataSetReader.Excel.OpenXmlFormat

MeshWeaver.DataSetReader.Excel.OpenXmlFormat is a specialized implementation for reading modern Excel (.xlsx) files using the Office Open XML format. It provides comprehensive support for reading Excel 2007+ workbooks with their XML-based structure.

Overview

The library provides:

• Complete Office Open XML format support
• Excel 2007+ workbook reading
• XML-based structure parsing
• Shared string handling
• Style and formatting support
• Cell type conversion

Architecture

Core Components

ExcelOpenXmlReader

Main reader implementation providing:

• ZIP archive handling
• XML content parsing
• Sheet data extraction
• Cell value conversion

Workbook Components

• XlsxWorkbook - Workbook structure and metadata
• XlsxWorksheet - Individual worksheet handling
• XlsxStyles - Style definitions and formatting
• XlsxDimension - Sheet dimensions and references

OpenXML Structure Support

Package Components

• Workbook XML
• Worksheet XMLs
• Shared Strings XML
• Styles XML
• Relationships XML

XML Namespaces

public static class Namespaces
{
    public const string SpreadsheetMl = 
        "http://schemas.openxmlformats.org/spreadsheetml/2006/main";
    public const string Relationships = 
        "http://schemas.openxmlformats.org/officeDocument/2006/relationships";
}

Usage Examples

Basic File Reading

public async Task<IDataSet> ReadXlsxFile(Stream stream)
{
    var reader = new ExcelOpenXmlReader();
    reader.Initialize(stream);
    
    var dataSet = new DataSet();
    while (reader.Read())
    {
        // Process rows
        for (int i = 0; i < reader.FieldCount; i++)
        {
            var value = reader.GetValue(i);
            // Handle cell value
        }
    }
    
    return dataSet;
}

Reading with Shared Strings

private object GetCellValue(XElement cell, XlsxWorkbook workbook)
{
    var cellType = cell.Attribute("t")?.Value;
    var value = cell.Element(ns + "v")?.Value;
    
    if (cellType == "s") // Shared string
    {
        return workbook.SharedStrings[int.Parse(value)];
    }
    
    return value;
}

Style Handling

private object FormatCellValue(object value, XlsxXf style)
{
    if (style.ApplyNumberFormat && IsDateTimeStyle(style.NumFmtId))
    {
        return ConvertFromOATime((double)value);
    }
    
    return value;
}

Advanced Features

ZIP Archive Handling

public class ZipWorker
{
    public Stream GetWorkbookStream()
    {
        return GetEntryStream("xl/workbook.xml");
    }
    
    public Stream GetSharedStringsStream()
    {
        return GetEntryStream("xl/sharedStrings.xml");
    }
}

Dimension Management

public class XlsxDimension
{
    public int FirstRow { get; }
    public int LastRow { get; }
    public int FirstCol { get; }
    public int LastCol { get; }
    
    public XlsxDimension(string reference)
    {
        // Parse Excel dimension reference (e.g., "A1:Z100")
    }
}

XML Structure

Workbook XML

<workbook xmlns="...">
  <sheets>
    <sheet name="Sheet1" sheetId="1" r:id="rId1"/>
    <sheet name="Sheet2" sheetId="2" r:id="rId2"/>
  </sheets>
</workbook>

Worksheet XML

<worksheet xmlns="...">
  <dimension ref="A1:Z100"/>
  <sheetData>
    <row r="1">
      <c r="A1" t="s">
        <v>0</v>
      </c>
    </row>
  </sheetData>
</worksheet>

Best Practices

1. Memory Management

   • Use streaming XML parsing
   • Handle large shared string tables
   • Manage ZIP archive resources
   • Clean up temporary streams

2. Performance

   • Cache shared strings
   • Optimize XML parsing
   • Use efficient cell access
   • Minimize memory allocations

3. Error Handling

   • Validate XML structure
   • Handle corrupt ZIP archives
   • Manage missing components
   • Validate cell references

4. Format Support

   • Handle all cell types
   • Support date/time formats
   • Process custom number formats
   • Manage style inheritance

Integration

With Base Excel Reader

public class OpenXmlFormatReader : ExcelDataSetReaderBase
{
    protected override IExcelDataReader GetExcelDataReader(Stream stream)
    {
        var reader = new ExcelOpenXmlReader();
        reader.Initialize(stream);
        return reader;
    }
}

With Message Hub

services.AddMessageHub(hub => hub
    .ConfigureServices(services => services
        .AddSingleton<IExcelReaderFactory>(provider => 
            new ExcelReaderFactory())
        .AddTransient<IDataSetReader, OpenXmlFormatReader>()
    )
);

Error Handling

The library provides detailed error information for:

• Invalid XML structure
• Corrupt ZIP archives
• Missing package parts
• Invalid cell references
• Format conversion errors

Related Projects

• MeshWeaver.DataSetReader.Excel - Base Excel reader framework
• MeshWeaver.DataSetReader.Excel.BinaryFormat - Legacy Excel format implementation
• MeshWeaver.DataStructures - Core data structures