C#でIronXLを使ってCSVファイルを読み込む方法

Install-Package IronXL
dotnet add package IronXL

using IronXL;

// Load CSV file into a workbook with one method call
WorkBook workbook = WorkBook.LoadCSV("sales_data.csv", fileFormat: ExcelFileFormat.XLSX, listDelimiter: ",");
// Access the default worksheet containing CSV data
WorkSheet sheet = workbook.DefaultWorkSheet;
// Display all rows and CSV columns
foreach (var row in sheet.Rows)
{
    foreach (var cell in row)
    {
        Console.Write(cell.Value + "\t");
    }
    Console.WriteLine();
}

Imports IronXL

' Load CSV file into a workbook with one method call
Dim workbook As WorkBook = WorkBook.LoadCSV("sales_data.csv", fileFormat:=ExcelFileFormat.XLSX, listDelimiter:=",")
' Access the default worksheet containing CSV data
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Display all rows and CSV columns
For Each row In sheet.Rows
    For Each cell In row
        Console.Write(cell.Value & vbTab)
    Next
    Console.WriteLine()
Next

using System.IO;

// Manual approach -- requires extensive code for basic functionality
string path = "data.csv";
string[] lines = File.ReadAllLines(path);
foreach (string line in lines)
{
    // This breaks when CSV fields contain commas inside quotes
    string[] fields = line.Split(',');
    foreach (string field in fields)
    {
        Console.Write(field.Trim() + "\t");
    }
    Console.WriteLine();
}

Imports System.IO

' Manual approach -- requires extensive code for basic functionality
Dim path As String = "data.csv"
Dim lines As String() = File.ReadAllLines(path)
For Each line As String In lines
    ' This breaks when CSV fields contain commas inside quotes
    Dim fields As String() = line.Split(","c)
    For Each field As String In fields
        Console.Write(field.Trim() & vbTab)
    Next
    Console.WriteLine()
Next

using IronXL;

// Reading a semicolon-delimited file (common in European exports)
WorkBook euroData = WorkBook.LoadCSV("german_report.csv", fileFormat: ExcelFileFormat.XLSX, listDelimiter: ";");
// Reading a tab-separated file
WorkBook tsvData = WorkBook.LoadCSV("exported_data.tsv", fileFormat: ExcelFileFormat.XLSX, listDelimiter: "\t");
// Reading a pipe-delimited file
WorkBook pipeData = WorkBook.LoadCSV("legacy_system.csv", fileFormat: ExcelFileFormat.XLSX, listDelimiter: "|");
// Access data identically regardless of original delimiter
WorkSheet sheet = euroData.DefaultWorkSheet;
int rowsCount = sheet.RowCount;
Console.WriteLine($"Loaded {rowsCount} rows with {sheet.ColumnCount} CSV columns");

Imports IronXL

' Reading a semicolon-delimited file (common in European exports)
Dim euroData As WorkBook = WorkBook.LoadCSV("german_report.csv", fileFormat:=ExcelFileFormat.XLSX, listDelimiter:=";")
' Reading a tab-separated file
Dim tsvData As WorkBook = WorkBook.LoadCSV("exported_data.tsv", fileFormat:=ExcelFileFormat.XLSX, listDelimiter:=vbTab)
' Reading a pipe-delimited file
Dim pipeData As WorkBook = WorkBook.LoadCSV("legacy_system.csv", fileFormat:=ExcelFileFormat.XLSX, listDelimiter:="|")
' Access data identically regardless of original delimiter
Dim sheet As WorkSheet = euroData.DefaultWorkSheet
Dim rowsCount As Integer = sheet.RowCount
Console.WriteLine($"Loaded {rowsCount} rows with {sheet.ColumnCount} CSV columns")

using IronXL;
using System.Data;

// Load CSV and convert to DataTable
WorkBook workbook = WorkBook.LoadCSV("customers.csv", ExcelFileFormat.XLSX, ",");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Convert worksheet to DataTable -- true parameter uses CSV header as column names
DataTable dataTable = sheet.ToDataTable(true);
// DataTable is now ready for database operations, binding, or LINQ queries
Console.WriteLine($"DataTable created with {dataTable.Columns.Count} columns:");
foreach (DataColumn column in dataTable.Columns)
{
    // Property names from CSV header become column names
    Console.WriteLine($"  - {column.ColumnName}");
}
Console.WriteLine($"\nTotal records: {dataTable.Rows.Count}");
// Access data using standard DataTable syntax
foreach (DataRow row in dataTable.Rows)
{
    // Access by column index or name attribute
    string name = row["Name"].ToString();
    string email = row["Email"].ToString();
    Console.WriteLine($"Customer: {name}, Email: {email}");
}

Imports IronXL
Imports System.Data

' Load CSV and convert to DataTable
Dim workbook As WorkBook = WorkBook.LoadCSV("customers.csv", ExcelFileFormat.XLSX, ",")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Convert worksheet to DataTable -- true parameter uses CSV header as column names
Dim dataTable As DataTable = sheet.ToDataTable(True)
' DataTable is now ready for database operations, binding, or LINQ queries
Console.WriteLine($"DataTable created with {dataTable.Columns.Count} columns:")
For Each column As DataColumn In dataTable.Columns
    ' Property names from CSV header become column names
    Console.WriteLine($"  - {column.ColumnName}")
Next
Console.WriteLine(vbCrLf & $"Total records: {dataTable.Rows.Count}")
' Access data using standard DataTable syntax
For Each row As DataRow In dataTable.Rows
    ' Access by column index or name attribute
    Dim name As String = row("Name").ToString()
    Dim email As String = row("Email").ToString()
    Console.WriteLine($"Customer: {name}, Email: {email}")
Next

using IronXL;

// Load CSV data from file path
string path = "quarterly_sales.csv";
WorkBook workbook = WorkBook.LoadCSV(path, ExcelFileFormat.XLSX, ",");
// Save as Excel XLSX format -- creates a new Excel file
workbook.SaveAs("quarterly_sales.xlsx");
// Alternative: Save as legacy XLS format for older Excel versions
workbook.SaveAs("quarterly_sales.xls");
Console.WriteLine("CSV successfully converted to Excel format");

Imports IronXL

' Load CSV data from file path
Dim path As String = "quarterly_sales.csv"
Dim workbook As WorkBook = WorkBook.LoadCSV(path, ExcelFileFormat.XLSX, ","c)
' Save as Excel XLSX format -- creates a new Excel file
workbook.SaveAs("quarterly_sales.xlsx")
' Alternative: Save as legacy XLS format for older Excel versions
workbook.SaveAs("quarterly_sales.xls")
Console.WriteLine("CSV successfully converted to Excel format")

using IronXL;

WorkBook workbook = WorkBook.LoadCSV("inventory.csv", ExcelFileFormat.XLSX, ",");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Access specific cells using Excel-style addresses by index
string productName = sheet["A2"].StringValue;
int quantity = sheet["B2"].IntValue;
decimal price = sheet["C2"].DecimalValue;
Console.WriteLine($"Product: {productName}");
Console.WriteLine($"Quantity: {quantity}");
Console.WriteLine($"Price: ${price:F2}");
// Access a range of cells -- return records from column A
var productRange = sheet["A2:A10"];
Console.WriteLine("\nAll products:");
foreach (var cell in productRange)
{
    Console.WriteLine($"  - {cell.StringValue}");
}

Imports IronXL

Dim workbook As WorkBook = WorkBook.LoadCSV("inventory.csv", ExcelFileFormat.XLSX, ",")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Access specific cells using Excel-style addresses by index
Dim productName As String = sheet("A2").StringValue
Dim quantity As Integer = sheet("B2").IntValue
Dim price As Decimal = sheet("C2").DecimalValue
Console.WriteLine($"Product: {productName}")
Console.WriteLine($"Quantity: {quantity}")
Console.WriteLine($"Price: ${price:F2}")
' Access a range of cells -- return records from column A
Dim productRange = sheet("A2:A10")
Console.WriteLine(vbCrLf & "All products:")
For Each cell In productRange
    Console.WriteLine($"  - {cell.StringValue}")
Next

using IronXL;
using System.IO;

string filePath = "customers.csv";
if (!File.Exists(filePath))
{
    Console.WriteLine($"File not found: {filePath}");
    return;
}
try
{
    WorkBook workbook = WorkBook.LoadCSV(filePath, ExcelFileFormat.XLSX, ",");
    WorkSheet sheet = workbook.DefaultWorkSheet;
    DataTable dataTable = sheet.ToDataTable(true);
    Console.WriteLine($"Loaded {dataTable.Rows.Count} records successfully.");
}
catch (IronXL.Exceptions.IronXLException ex)
{
    Console.WriteLine($"IronXL parsing error: {ex.Message}");
}
catch (IOException ex)
{
    Console.WriteLine($"File access error: {ex.Message}");
}
catch (Exception ex)
{
    Console.WriteLine($"Unexpected error: {ex.Message}");
}

Imports IronXL
Imports System.IO

Dim filePath As String = "customers.csv"
If Not File.Exists(filePath) Then
    Console.WriteLine($"File not found: {filePath}")
    Return
End If

Try
    Dim workbook As WorkBook = WorkBook.LoadCSV(filePath, ExcelFileFormat.XLSX, ",")
    Dim sheet As WorkSheet = workbook.DefaultWorkSheet
    Dim dataTable As DataTable = sheet.ToDataTable(True)
    Console.WriteLine($"Loaded {dataTable.Rows.Count} records successfully.")
Catch ex As IronXL.Exceptions.IronXLException
    Console.WriteLine($"IronXL parsing error: {ex.Message}")
Catch ex As IOException
    Console.WriteLine($"File access error: {ex.Message}")
Catch ex As Exception
    Console.WriteLine($"Unexpected error: {ex.Message}")
End Try