ExcelDataReaderがExcelファイルを書き込めない理由とIronXLがこれを解決する方法

Can ExcelDataReader Write Excel Workbook Data?

No, ExcelDataReader cannot write Excel files. This library is designed exclusively for reading Excel documents in various formats (XLS, XLSX, CSV), and while it is a fast library written for reading Excel files in C#, this is really all it's built for. The official GitHub repository even explicitly states it's a "library for reading Microsoft Excel files" with no writing capabilities. When you install the package and reference the dll in your project, you'll find it cannot handle encoding for writing, skip rows to fix data issues, or deal with column names and int values in generic collections.

Here's what ExcelDataReader can do, requiring a new excelreaderconfiguration instance to handle filepath and memory settings for server deployments:

Here's what ExcelDataReader can do:

using ExcelDataReader;
using System.IO;
// ExcelDataReader can ONLY read files
using (var stream = File.Open("data.xlsx", FileMode.Open, FileAccess.Read))
{
    using (var reader = ExcelReaderFactory.CreateReader(stream))
    {
        // Read data from Excel
        while (reader.Read())
        {
            var value = reader.GetString(0); // Read cell value
        }
        // But there's no way to write back to the file
    }
}

using ExcelDataReader;
using System.IO;
// ExcelDataReader can ONLY read files
using (var stream = File.Open("data.xlsx", FileMode.Open, FileAccess.Read))
{
    using (var reader = ExcelReaderFactory.CreateReader(stream))
    {
        // Read data from Excel
        while (reader.Read())
        {
            var value = reader.GetString(0); // Read cell value
        }
        // But there's no way to write back to the file
    }
}

IRON VB CONVERTER ERROR developers@ironsoftware.com

This code demonstrates ExcelDataReader's read-only nature. The library efficiently extracts data from Excel files but provides no methods like Write(), Save(), or SetCellValue(). Developers needing to create reports, update spreadsheets, generate new Excel files, record information, post results to other systems, comment on cells, implement linq queries, or populate tags and metadata must look elsewhere.

How Does IronXL Solve the Writing Problem?

IronXL provides complete Excel manipulation capabilities, allowing developers to read, create, edit, and save Excel files without Microsoft Office dependencies. Unlike read-only solutions, IronXL treats Excel files as fully editable documents. This straightforward approach lets you deal with csv data, convert between formats, and populate sheets seamlessly.

Install-Package IronXL.Excel

using IronXL;
// Your first IronXL application
class Program
{
    static void Main()
    {
        // Create workbook
        WorkBook workBook = WorkBook.Create();
        WorkSheet sheet = workBook.CreateWorkSheet("Data");    
        // Write your data
        sheet["A1"].Value = "Hello Excel";
        // Save to file
        workBook.SaveAs("output.xlsx");
    }
}

using IronXL;
// Your first IronXL application
class Program
{
    static void Main()
    {
        // Create workbook
        WorkBook workBook = WorkBook.Create();
        WorkSheet sheet = workBook.CreateWorkSheet("Data");    
        // Write your data
        sheet["A1"].Value = "Hello Excel";
        // Save to file
        workBook.SaveAs("output.xlsx");
    }
}

IRON VB CONVERTER ERROR developers@ironsoftware.com

using IronXL;
// Create a new Excel file
WorkBook workBook = WorkBook.Create();
WorkSheet sheet = workBook.CreateWorkSheet("Report");
// Write values to specific cells
sheet["A1"].Value = "Product";
sheet["B1"].Value = "Quantity";
sheet["A2"].Value = "Widget";
sheet["B2"].Value = 100;
// Save the file
workBook.SaveAs("inventory.xlsx");

using IronXL;
// Create a new Excel file
WorkBook workBook = WorkBook.Create();
WorkSheet sheet = workBook.CreateWorkSheet("Report");
// Write values to specific cells
sheet["A1"].Value = "Product";
sheet["B1"].Value = "Quantity";
sheet["A2"].Value = "Widget";
sheet["B2"].Value = 100;
// Save the file
workBook.SaveAs("inventory.xlsx");

IRON VB CONVERTER ERROR developers@ironsoftware.com

// Write formulas
sheet["C1"].Value = "Total";
sheet["C2"].Formula = "=B2*1.5";
// Write ranges efficiently
sheet["A3:A10"].Value = "Item";
// Apply formatting while writing
sheet["B2"].Style.Font.Bold = true;
sheet["B2"].Style.BackgroundColor = "#FFFF00";

// Write formulas
sheet["C1"].Value = "Total";
sheet["C2"].Formula = "=B2*1.5";
// Write ranges efficiently
sheet["A3:A10"].Value = "Item";
// Apply formatting while writing
sheet["B2"].Style.Font.Bold = true;
sheet["B2"].Style.BackgroundColor = "#FFFF00";

IRON VB CONVERTER ERROR developers@ironsoftware.com

What's the Implementation Difference?

The fundamental difference becomes clear when comparing typical workflows. Consider a common requirement: reading data from one Excel file and creating a modified version.

// Read with ExcelDataReader
List<string> data = new List<string>();
using (var stream = File.Open("source.xlsx", FileMode.Open))
{
    using (var reader = ExcelReaderFactory.CreateReader(stream))
    {
        while (reader.Read())
        {
            data.Add(reader.GetString(0));
        }
    }
}
// Cannot write back to Excel - need another library!

// Read with ExcelDataReader
List<string> data = new List<string>();
using (var stream = File.Open("source.xlsx", FileMode.Open))
{
    using (var reader = ExcelReaderFactory.CreateReader(stream))
    {
        while (reader.Read())
        {
            data.Add(reader.GetString(0));
        }
    }
}
// Cannot write back to Excel - need another library!

IRON VB CONVERTER ERROR developers@ironsoftware.com

// Read and write with IronXL
WorkBook workBook = WorkBook.Load("source.xlsx");
WorkSheet sheet = workBook.DefaultWorkSheet;
// Read existing data
string originalValue = sheet["A1"].StringValue;
// Modify and add new data
sheet["A1"].Value = originalValue.ToUpper();
sheet["B1"].Value = DateTime.Now;
// Save as new file
workBook.SaveAs("modified.xlsx");

// Read and write with IronXL
WorkBook workBook = WorkBook.Load("source.xlsx");
WorkSheet sheet = workBook.DefaultWorkSheet;
// Read existing data
string originalValue = sheet["A1"].StringValue;
// Modify and add new data
sheet["A1"].Value = originalValue.ToUpper();
sheet["B1"].Value = DateTime.Now;
// Save as new file
workBook.SaveAs("modified.xlsx");

IRON VB CONVERTER ERROR developers@ironsoftware.com

When Should You Use IronXL?

IronXL becomes essential when your application requires:

• Report Generation: Creating Excel reports from database queries or API responses
• Data Export: Converting application and CSV data to Excel format for users
• Template Processing: Filling Excel templates with dynamic data
• Spreadsheet Automation: Updating existing files with new information
• Batch Processing: Modifying multiple Excel files programmatically

These scenarios are impossible with ExcelDataReader alone. While ExcelDataReader excels at extracting data from existing files, any requirement to produce or modify Excel documents necessitates a library with writing capabilities. When you need to implement solutions that convert data, populate column names from array objects, fix formatting issues, record changes, or post results to a server, IronXL provides the complete toolset.

Business applications particularly benefit from IronXL's comprehensive features. Whether generating invoices, creating inventory reports, or producing financial statements, the ability to both read source data and write formatted output streamlines development.

結論

ExcelDataReader serves a specific purpose: efficiently reading Excel files. However, modern applications typically require bidirectional Excel interaction. IronXL addresses this need by providing complete Excel manipulation capabilities in a single, cohesive library. Instead of combining multiple tools or working around limitations, developers can handle all Excel operations with one consistent API.

Ready to move beyond read-only Excel operations? Start with IronXL's free trial to experience complete Excel control in your .NET applications. For production use, explore licensing options that include dedicated support and deployment flexibility.