C# 列ヘッダー付きの DataGridView を Excel にエクスポートする

Install-Package IronXL

dotnet add package IronXL

using IronXL;
using System;
using System.Data;
using System.Windows.Forms;

Imports IronXL
Imports System
Imports System.Data
Imports System.Windows.Forms

using System;
using System.Data;
using System.Windows.Forms;

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        DataTable dt = new DataTable();

        // Define columns -- these names become Excel headers
        dt.Columns.Add("Product ID", typeof(int));
        dt.Columns.Add("Product Name", typeof(string));
        dt.Columns.Add("Price", typeof(decimal));
        dt.Columns.Add("Stock Quantity", typeof(int));

        // Add sample rows
        dt.Rows.Add(1001, "Laptop", 999.99m, 15);
        dt.Rows.Add(1002, "Mouse", 29.99m, 50);
        dt.Rows.Add(1003, "Keyboard", 79.99m, 30);
        dt.Rows.Add(1004, "Monitor", 299.99m, 12);
        dt.Rows.Add(1005, "Headphones", 89.99m, 25);

        // Bind data to the grid
        dataGridView1.DataSource = dt;
    }
}

Imports System
Imports System.Data
Imports System.Windows.Forms

Public Partial Class Form1
    Inherits Form

    Public Sub New()
        InitializeComponent()
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim dt As New DataTable()

        ' Define columns -- these names become Excel headers
        dt.Columns.Add("Product ID", GetType(Integer))
        dt.Columns.Add("Product Name", GetType(String))
        dt.Columns.Add("Price", GetType(Decimal))
        dt.Columns.Add("Stock Quantity", GetType(Integer))

        ' Add sample rows
        dt.Rows.Add(1001, "Laptop", 999.99D, 15)
        dt.Rows.Add(1002, "Mouse", 29.99D, 50)
        dt.Rows.Add(1003, "Keyboard", 79.99D, 30)
        dt.Rows.Add(1004, "Monitor", 299.99D, 12)
        dt.Rows.Add(1005, "Headphones", 89.99D, 25)

        ' Bind data to the grid
        dataGridView1.DataSource = dt
    End Sub
End Class

private void btnExport_Click(object sender, EventArgs e)
{
    try
    {
        // Create a new Excel workbook in XLSX format
        WorkBook workbook = WorkBook.Create(ExcelFileFormat.XLSX);
        WorkSheet worksheet = workbook.CreateWorkSheet("Exported Data");

        // Write column headers to row 0
        for (int col = 0; col < dataGridView1.Columns.Count; col++)
        {
            worksheet.SetCellValue(0, col, dataGridView1.Columns[col].HeaderText);
        }

        // Write data rows starting at row 1
        for (int row = 0; row < dataGridView1.Rows.Count; row++)
        {
            // Skip the placeholder new-row at the bottom of the grid
            if (dataGridView1.AllowUserToAddRows && row == dataGridView1.Rows.Count - 1)
                continue;

            for (int col = 0; col < dataGridView1.Columns.Count; col++)
            {
                var cellValue = dataGridView1.Rows[row].Cells[col].Value;
                if (cellValue != null)
                {
                    worksheet.SetCellValue(row + 1, col, cellValue.ToString());
                }
            }
        }

        // Prompt the user to choose a save location
        using SaveFileDialog saveFileDialog = new SaveFileDialog
        {
            Filter = "Excel Files|*.xlsx",
            FileName = "DataGridView_Export.xlsx"
        };

        if (saveFileDialog.ShowDialog() == DialogResult.OK)
        {
            workbook.SaveAs(saveFileDialog.FileName);
            MessageBox.Show("Export completed successfully!", "Success",
                            MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show($"Export failed: {ex.Message}", "Error",
                       MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

Private Sub btnExport_Click(sender As Object, e As EventArgs)
    Try
        ' Create a new Excel workbook in XLSX format
        Dim workbook As WorkBook = WorkBook.Create(ExcelFileFormat.XLSX)
        Dim worksheet As WorkSheet = workbook.CreateWorkSheet("Exported Data")

        ' Write column headers to row 0
        For col As Integer = 0 To dataGridView1.Columns.Count - 1
            worksheet.SetCellValue(0, col, dataGridView1.Columns(col).HeaderText)
        Next

        ' Write data rows starting at row 1
        For row As Integer = 0 To dataGridView1.Rows.Count - 1
            ' Skip the placeholder new-row at the bottom of the grid
            If dataGridView1.AllowUserToAddRows AndAlso row = dataGridView1.Rows.Count - 1 Then
                Continue For
            End If

            For col As Integer = 0 To dataGridView1.Columns.Count - 1
                Dim cellValue = dataGridView1.Rows(row).Cells(col).Value
                If cellValue IsNot Nothing Then
                    worksheet.SetCellValue(row + 1, col, cellValue.ToString())
                End If
            Next
        Next

        ' Prompt the user to choose a save location
        Using saveFileDialog As New SaveFileDialog With {
            .Filter = "Excel Files|*.xlsx",
            .FileName = "DataGridView_Export.xlsx"
        }
            If saveFileDialog.ShowDialog() = DialogResult.OK Then
                workbook.SaveAs(saveFileDialog.FileName)
                MessageBox.Show("Export completed successfully!", "Success",
                                MessageBoxButtons.OK, MessageBoxIcon.Information)
            End If
        End Using
    Catch ex As Exception
        MessageBox.Show($"Export failed: {ex.Message}", "Error",
                       MessageBoxButtons.OK, MessageBoxIcon.Error)
    End Try
End Sub

WorkBook csvWorkbook = WorkBook.Create(ExcelFileFormat.CSV);
WorkSheet csvSheet = csvWorkbook.CreateWorkSheet("Data");

// Headers and data loops remain identical

using SaveFileDialog dialog = new SaveFileDialog
{
    Filter = "CSV Files|*.csv",
    FileName = "DataGridView_Export.csv"
};

if (dialog.ShowDialog() == DialogResult.OK)
    csvWorkbook.SaveAs(dialog.FileName);

Imports System.Windows.Forms

Dim csvWorkbook As WorkBook = WorkBook.Create(ExcelFileFormat.CSV)
Dim csvSheet As WorkSheet = csvWorkbook.CreateWorkSheet("Data")

' Headers and data loops remain identical

Using dialog As New SaveFileDialog With {
    .Filter = "CSV Files|*.csv",
    .FileName = "DataGridView_Export.csv"
}
    If dialog.ShowDialog() = DialogResult.OK Then
        csvWorkbook.SaveAs(dialog.FileName)
    End If
End Using

// Write headers and apply bold styling
for (int col = 0; col < dataGridView1.Columns.Count; col++)
{
    string cellAddress = worksheet.GetCellAddress(0, col);
    worksheet[cellAddress].Value = dataGridView1.Columns[col].HeaderText;
    worksheet[cellAddress].Style.Font.Bold = true;
    worksheet[cellAddress].Style.SetBackgroundColor("#4472C4");
    worksheet[cellAddress].Style.Font.FontColor = "#FFFFFF";
}

' Write headers and apply bold styling
For col As Integer = 0 To dataGridView1.Columns.Count - 1
    Dim cellAddress As String = worksheet.GetCellAddress(0, col)
    worksheet(cellAddress).Value = dataGridView1.Columns(col).HeaderText
    worksheet(cellAddress).Style.Font.Bold = True
    worksheet(cellAddress).Style.SetBackgroundColor("#4472C4")
    worksheet(cellAddress).Style.Font.FontColor = "#FFFFFF"
Next col

IronXL.License.LicenseKey = "YOUR-LICENSE-KEY-HERE";

Imports IronXL

IronXL.License.LicenseKey = "YOUR-LICENSE-KEY-HERE"