C# で CSV をインポートする | ASP.NET Coreチュートリアル | IronXL

Install-Package IronXL.Excel
dotnet add package IronXL.Excel

using IronXL;

// Load the CSV file directly using the full file path
var csv = WorkBook.LoadCSV("products.csv");
WorkSheet worksheet = csv.DefaultWorkSheet;

// Access CSV data by iterating through rows
foreach (var row in worksheet.Rows)
{
    string productName = row.Columns[1].StringValue;
    decimal price = row.Columns[2].DecimalValue;
    Console.WriteLine($"Product: {productName}, Price: {price}");
}

Imports IronXL

' Load the CSV file directly using the full file path
Dim csv = WorkBook.LoadCSV("products.csv")
Dim worksheet As WorkSheet = csv.DefaultWorkSheet

' Access CSV data by iterating through rows
For Each row In worksheet.Rows
    Dim productName As String = row.Columns(1).StringValue
    Dim price As Decimal = row.Columns(2).DecimalValue
    Console.WriteLine($"Product: {productName}, Price: {price}")
Next

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; } = string.Empty;
    public decimal Price { get; set; }
    public int Quantity { get; set; }
}

Public Class Product
    Public Property Id As Integer
    Public Property Name As String = String.Empty
    Public Property Price As Decimal
    Public Property Quantity As Integer
End Class

using IronXL;
using Microsoft.AspNetCore.Mvc;

[Route("api/[controller]")]
[ApiController]
public class CsvController : ControllerBase
{
    [HttpPost("upload")]
    public async Task<IActionResult> UploadCsv(IFormFile file)
    {
        if (file == null || file.Length == 0)
            return BadRequest("Please upload a valid CSV file.");

        try
        {
            using var stream = new MemoryStream();
            await file.CopyToAsync(stream);
            stream.Position = 0;

            WorkBook workbook = WorkBook.Load(stream, "csv");
            WorkSheet ws = workbook.DefaultWorkSheet;
            var records = new List<Product>();

            // Skip header row, iterate through data rows
            for (int i = 1; i < ws.Rows.Count(); i++)
            {
                var row = ws.Rows[i];
                records.Add(new Product
                {
                    Id = row.Columns[0].IntValue,
                    Name = row.Columns[1].StringValue,
                    Price = row.Columns[2].DecimalValue,
                    Quantity = row.Columns[3].IntValue
                });
            }

            return Ok(new
            {
                message = "Import successful",
                count = records.Count,
                data = records
            });
        }
        catch (Exception ex)
        {
            return BadRequest($"Error processing file: {ex.Message}");
        }
    }
}

Imports IronXL
Imports Microsoft.AspNetCore.Mvc
Imports System.IO
Imports System.Threading.Tasks

<Route("api/[controller]")>
<ApiController>
Public Class CsvController
    Inherits ControllerBase

    <HttpPost("upload")>
    Public Async Function UploadCsv(file As IFormFile) As Task(Of IActionResult)
        If file Is Nothing OrElse file.Length = 0 Then
            Return BadRequest("Please upload a valid CSV file.")
        End If

        Try
            Using stream As New MemoryStream()
                Await file.CopyToAsync(stream)
                stream.Position = 0

                Dim workbook As WorkBook = WorkBook.Load(stream, "csv")
                Dim ws As WorkSheet = workbook.DefaultWorkSheet
                Dim records As New List(Of Product)()

                ' Skip header row, iterate through data rows
                For i As Integer = 1 To ws.Rows.Count() - 1
                    Dim row = ws.Rows(i)
                    records.Add(New Product With {
                        .Id = row.Columns(0).IntValue,
                        .Name = row.Columns(1).StringValue,
                        .Price = row.Columns(2).DecimalValue,
                        .Quantity = row.Columns(3).IntValue
                    })
                Next

                Return Ok(New With {
                    .message = "Import successful",
                    .count = records.Count,
                    .data = records
                })
            End Using
        Catch ex As Exception
            Return BadRequest($"Error processing file: {ex.Message}")
        End Try
    End Function
End Class

using IronXL;

public class CsvImportService
{
    private readonly AppDbContext _context;

    public CsvImportService(AppDbContext context)
    {
        _context = context;
    }

    public async Task<int> ImportProductsAsync(Stream csvStream)
    {
        WorkBook workbook = WorkBook.LoadCSV(csvStream);
        WorkSheet ws = workbook.DefaultWorkSheet;
        var products = new List<Product>();

        foreach (var row in ws.Rows.Skip(1))
        {
            products.Add(new Product
            {
                Id = row.Columns[0].IntValue,
                Name = row.Columns[1].StringValue,
                Price = row.Columns[2].DecimalValue,
                Quantity = row.Columns[3].IntValue
            });
        }

        await _context.Products.AddRangeAsync(products);
        return await _context.SaveChangesAsync();
    }
}

Imports IronXL

Public Class CsvImportService
    Private ReadOnly _context As AppDbContext

    Public Sub New(context As AppDbContext)
        _context = context
    End Sub

    Public Async Function ImportProductsAsync(csvStream As Stream) As Task(Of Integer)
        Dim workbook As WorkBook = WorkBook.LoadCSV(csvStream)
        Dim ws As WorkSheet = workbook.DefaultWorkSheet
        Dim products As New List(Of Product)()

        For Each row In ws.Rows.Skip(1)
            products.Add(New Product With {
                .Id = row.Columns(0).IntValue,
                .Name = row.Columns(1).StringValue,
                .Price = row.Columns(2).DecimalValue,
                .Quantity = row.Columns(3).IntValue
            })
        Next

        Await _context.Products.AddRangeAsync(products)
        Return Await _context.SaveChangesAsync()
    End Function
End Class

using IronXL;

WorkBook workbook = WorkBook.Create(ExcelFileFormat.XLS);
WorkSheet ws = workbook.DefaultWorkSheet;

// Write headers
ws["A1"].Value = "Id";
ws["B1"].Value = "Name";
ws["C1"].Value = "Price";

// Write data rows
ws["A2"].Value = 1;
ws["B2"].Value = "Widget A";
ws["C2"].Value = 9.99;

ws["A3"].Value = 2;
ws["B3"].Value = "Widget B";
ws["C3"].Value = 14.49;

// Save as CSV
workbook.SaveAsCsv("export.csv");
Console.WriteLine("CSV export complete.");

Imports IronXL

Dim workbook As WorkBook = WorkBook.Create(ExcelFileFormat.XLS)
Dim ws As WorkSheet = workbook.DefaultWorkSheet

' Write headers
ws("A1").Value = "Id"
ws("B1").Value = "Name"
ws("C1").Value = "Price"

' Write data rows
ws("A2").Value = 1
ws("B2").Value = "Widget A"
ws("C2").Value = 9.99

ws("A3").Value = 2
ws("B3").Value = "Widget B"
ws("C3").Value = 14.49

' Save as CSV
workbook.SaveAsCsv("export.csv")
Console.WriteLine("CSV export complete.")