MeshWeaver.DataSetReader.Excel.Utils 2.5.0

MeshWeaver.DataSetReader.Excel.Utils

MeshWeaver.DataSetReader.Excel.Utils is a utility library that provides common functionality and abstractions for Excel file reading in the MeshWeaver ecosystem. It serves as the foundation for both binary (.xls) and OpenXML (.xlsx) format readers.

Overview

The library provides:

• Core interfaces for Excel data reading
• Common utility functions for Excel data processing
• Error handling and exception types
• ZIP archive handling for OpenXML formats
• Format conversion utilities
• Data type management

Core Components

IExcelDataReader Interface

The main interface for Excel data reading implementations:

public interface IExcelDataReader : IDataReader
{
 void Initialize(Stream fileStream);
 DataSet AsDataSet();
 DataSet AsDataSet(bool convertOADateTime);
 bool IsValid { get; }
 string Name { get; }
 int ResultsCount { get; }
 bool IsFirstRowAsColumnNames { get; set; }
}

Utility Functions

Data Conversion

public static class Helpers
{
 // Convert Excel OLE Automation date to DateTime
 public static object ConvertFromOATime(double value);
 
 // Convert escaped characters in strings
 public static string ConvertEscapeChars(string input);
 
 // Convert Int64 bits to double (for binary formats)
 public static double Int64BitsToDouble(long value);
}

Data Type Management

public static class Helpers
{
 // Fix and optimize data types in DataSet
 public static void FixDataTypes(DataSet dataset);
 
 // Handle duplicate column names
 public static void AddColumnHandleDuplicate(DataTable table, string columnName);
}

ZIP Archive Handling

public class ZipWorker
{
 // Access workbook and shared strings streams
 public Stream GetWorkbookStream();
 public Stream GetSharedStringsStream();
 public Stream GetStylesStream();
}

Constants and Formats

public static class ExcelConstants
{
 // Common Excel format constants
 public const int MaxWorksheetColumns = 16384;
 public const int MaxWorksheetRows = 1048576;
 public const int MaxWorksheetNameLength = 31;
}

Error Handling

Exception Types

• BiffRecordException - For BIFF record parsing errors
• HeaderException - For header parsing errors
• ExcelReaderException - Base exception for Excel reading errors

Error Messages

public static class Errors
{
 public const string InvalidPassword = "Invalid password";
 public const string InvalidFile = "Invalid file";
 public const string NotSupported = "Not supported";
}

Features

1. Format Support

   • Binary (.xls) format utilities
   • OpenXML (.xlsx) format utilities
   • Common abstractions for both formats

2. Data Processing

   • Stream-based reading
   • Data type inference
   • Column name handling
   • Date/time conversion
   • Character encoding support

3. Error Handling

   • Specialized exception types
   • Validation checks
   • Error messages
   • Recovery mechanisms

4. Performance Optimizations

   • Efficient data type handling
   • Stream management
   • Memory optimization
   • Resource cleanup

Best Practices

1. Resource Management

   using (var stream = File.OpenRead("data.xlsx"))
   {
    var reader = new ExcelReader();
    reader.Initialize(stream);
    // Process data
   }
   

2. Data Type Handling

   var dataset = reader.AsDataSet();
   Helpers.FixDataTypes(dataset); // Optimize data types
   

3. Error Handling

   try
   {
    reader.Initialize(stream);
    if (!reader.IsValid)
    throw new ExcelReaderException(reader.ExceptionMessage);
   }
   catch (BiffRecordException ex)
   {
    // Handle BIFF format errors
   }
   

Integration

With Excel Readers

public class ExcelReader : IExcelDataReader
{
 protected readonly ZipWorker ZipWorker;
 
 public void Initialize(Stream stream)
 {
 ZipWorker.Initialize(stream);
 // Initialize reader
 }
}

With Message Hub

services.AddMessageHub(hub => hub
 .ConfigureServices(services => services
 .AddTransient<IExcelDataReader, ExcelReader>()
 )
);

Related Projects

• MeshWeaver.DataSetReader.Excel - Base Excel reader framework
• MeshWeaver.DataSetReader.Excel.BinaryFormat - Legacy Excel format implementation
• MeshWeaver.DataSetReader.Excel.OpenXmlFormat - Modern Excel format implementation