BlazorでIronXLを使用してExcelにエクスポートする方法

window.downloadFileFromStream = async (fileName, contentStreamReference) => {
    const arrayBuffer = await contentStreamReference.arrayBuffer();
    const blob = new Blob([arrayBuffer]);
    const url = URL.createObjectURL(blob);
    const anchorElement = document.createElement('a');
    anchorElement.href = url;
    anchorElement.download = fileName ?? 'export.xlsx';
    anchorElement.click();
    anchorElement.remove();
    URL.revokeObjectURL(url);
}

<script src="~/excelExport.js"></script>

using IronXL;
using System.IO;
using ExportExcel.Models;
public class ExcelExportService
{
    public byte[] GenerateSalesReport(List<SalesData> salesData)
    {
        try
        {
            var workbook = WorkBook.Create(ExcelFileFormat.XLSX);
            workbook.Metadata.Author = "Sales Department";
            var worksheet = workbook.CreateWorkSheet("Monthly Sales");
            worksheet["A1"].Value = "Date";
            worksheet["B1"].Value = "Product";
            worksheet["C1"].Value = "Quantity";
            worksheet["D1"].Value = "Revenue";
            worksheet["E1"].Value = "Profit Margin";
            var headerRange = worksheet["A1:E1"];
            headerRange.Style.Font.Bold = true;
            headerRange.Style.BackgroundColor = "#4472C4";
            headerRange.Style.Font.Color = "#FFFFFF";
            int row = 2;
            foreach (var sale in salesData)
            {
                worksheet[$"A{row}"].Value = sale.Date.ToString("yyyy-MM-dd");
                worksheet[$"B{row}"].Value = sale.Product ?? "Unknown";
                worksheet[$"C{row}"].Value = sale.Quantity;
                worksheet[$"D{row}"].Value = sale.Revenue;
                worksheet[$"E{row}"].Value = $"=D{row}*0.15";
                row++;
            }
            worksheet.AutoSizeColumn(0, true);
            using var ms = workbook.ToStream();
            return ms.ToArray();
        }
        catch (Exception ex)
        {
        // If the program fails to return file
            throw new InvalidOperationException("Failed to generate sales report", ex);
        }
    }
}

Imports IronXL
Imports System.IO
Imports ExportExcel.Models

Public Class ExcelExportService
    Public Function GenerateSalesReport(salesData As List(Of SalesData)) As Byte()
        Try
            Dim workbook = WorkBook.Create(ExcelFileFormat.XLSX)
            workbook.Metadata.Author = "Sales Department"
            Dim worksheet = workbook.CreateWorkSheet("Monthly Sales")
            worksheet("A1").Value = "Date"
            worksheet("B1").Value = "Product"
            worksheet("C1").Value = "Quantity"
            worksheet("D1").Value = "Revenue"
            worksheet("E1").Value = "Profit Margin"
            Dim headerRange = worksheet("A1:E1")
            headerRange.Style.Font.Bold = True
            headerRange.Style.BackgroundColor = "#4472C4"
            headerRange.Style.Font.Color = "#FFFFFF"
            Dim row As Integer = 2
            For Each sale In salesData
                worksheet($"A{row}").Value = sale.Date.ToString("yyyy-MM-dd")
                worksheet($"B{row}").Value = If(sale.Product, "Unknown")
                worksheet($"C{row}").Value = sale.Quantity
                worksheet($"D{row}").Value = sale.Revenue
                worksheet($"E{row}").Value = $"=D{row}*0.15"
                row += 1
            Next
            worksheet.AutoSizeColumn(0, True)
            Using ms = workbook.ToStream()
                Return ms.ToArray()
            End Using
        Catch ex As Exception
            ' If the program fails to return file
            Throw New InvalidOperationException("Failed to generate sales report", ex)
        End Try
    End Function
End Class

@page "/excel-export"
@using ExportExcel.Models
@inject ExcelExportService ExcelService
@inject IJSRuntime JS
<h3>Excel Export Dashboard</h3>
<div class="export-section">
    <button class="btn btn-primary" @onclick="ExportSalesReport" disabled="@isExporting">
        @if (isExporting)
        {
            <span>Generating...</span>
        }
        else
        {
            <span>Export Sales Report</span>
        }
    </button>
    @if (!string.IsNullOrEmpty(errorMessage))
    {
        <div class="alert alert-danger mt-2">@errorMessage</div>
    }
</div>
@code {
    private bool isExporting = false;
    private string errorMessage = "";
    private async Task ExportSalesReport()
    {
        try
        {
            isExporting = true;
            errorMessage = "";
            // Generate sample data - replace with actual data source
            var salesData = GetSalesData();
            // Generate Excel file
            var fileBytes = ExcelService.GenerateSalesReport(salesData);
            // Trigger download using a memory stream to handle the file
            using var stream = new MemoryStream(fileBytes);
            using var streamRef = new DotNetStreamReference(stream);
            await JS.InvokeVoidAsync("downloadFileFromStream",
                $"SalesReport_{DateTime.Now:yyyyMMdd}.xlsx", streamRef);
        }
        catch (Exception ex)
        {
            errorMessage = "Export failed. Please try again.";
            // Log exception details for debugging
        }
        finally
        {
            isExporting = false;
        }
    }
    private List<SalesData> GetSalesData()
    {
        // Return your actual data here
        return new List<SalesData>
        {
            new() { Date = DateTime.Now, Product = "Widget A",
                   Quantity = 100, Revenue = 5000 },
            new() { Date = DateTime.Now.AddDays(-1), Product = "Widget B",
                   Quantity = 75, Revenue = 3750 }
        };
    }
}

@page "/excel-export"
@Imports ExportExcel.Models
@inject ExcelExportService ExcelService
@inject IJSRuntime JS
<h3>Excel Export Dashboard</h3>
<div class="export-section">
    <button class="btn btn-primary" @onclick="ExportSalesReport" disabled="@isExporting">
        @If isExporting Then
            <span>Generating...</span>
        Else
            <span>Export Sales Report</span>
        End If
    </button>
    @If Not String.IsNullOrEmpty(errorMessage) Then
        <div class="alert alert-danger mt-2">@errorMessage</div>
    End If
</div>
@code {
    Private isExporting As Boolean = False
    Private errorMessage As String = ""
    Private Async Function ExportSalesReport() As Task
        Try
            isExporting = True
            errorMessage = ""
            ' Generate sample data - replace with actual data source
            Dim salesData = GetSalesData()
            ' Generate Excel file
            Dim fileBytes = ExcelService.GenerateSalesReport(salesData)
            ' Trigger download using a memory stream to handle the file
            Using stream As New MemoryStream(fileBytes)
                Using streamRef As New DotNetStreamReference(stream)
                    Await JS.InvokeVoidAsync("downloadFileFromStream", $"SalesReport_{DateTime.Now:yyyyMMdd}.xlsx", streamRef)
                End Using
            End Using
        Catch ex As Exception
            errorMessage = "Export failed. Please try again."
            ' Log exception details for debugging
        Finally
            isExporting = False
        End Try
    End Function

    Private Function GetSalesData() As List(Of SalesData)
        ' Return your actual data here
        Return New List(Of SalesData) From {
            New SalesData With {.Date = DateTime.Now, .Product = "Widget A", .Quantity = 100, .Revenue = 5000},
            New SalesData With {.Date = DateTime.Now.AddDays(-1), .Product = "Widget B", .Quantity = 75, .Revenue = 3750}
        }
    End Function
}

using IronXL;
using ExportExcel.Models;
using System.IO;
namespace ExportExcel.Services
{
    public class InventoryExportService
    {
        public byte[] GenerateInventoryReport(List<InventoryItem> items)
        {
            var workbook = WorkBook.Create();
            var details = workbook.CreateWorkSheet("Inventory Details");
            // Add headers
            details["A1"].Value = "SKU";
            details["B1"].Value = "Name";
            details["C1"].Value = "Quantity";
            // Apply bold font for headers
            var headerRange = details["A1:C1"];
            headerRange.Style.Font.Bold = true;
            for (int i = 0; i < items.Count; i++)
            {
                var row = i + 2; // start from row 2
                var item = items[i];
                details[$"A{row}"].Value = item.SKU;
                details[$"B{row}"].Value = item.Name;
                details[$"C{row}"].Value = item.Quantity;
                // Highlight low stock items
                if (item.Quantity < item.ReorderLevel)
                {
                    details[$"C{row}"].Style.BackgroundColor = "#FFB6B6";
                }
            }
            using var stream = workbook.ToStream();
            return stream.ToArray();
        }
    }
}

Imports IronXL
Imports ExportExcel.Models
Imports System.IO

Namespace ExportExcel.Services
    Public Class InventoryExportService
        Public Function GenerateInventoryReport(items As List(Of InventoryItem)) As Byte()
            Dim workbook = WorkBook.Create()
            Dim details = workbook.CreateWorkSheet("Inventory Details")
            ' Add headers
            details("A1").Value = "SKU"
            details("B1").Value = "Name"
            details("C1").Value = "Quantity"
            ' Apply bold font for headers
            Dim headerRange = details("A1:C1")
            headerRange.Style.Font.Bold = True
            For i As Integer = 0 To items.Count - 1
                Dim row = i + 2 ' start from row 2
                Dim item = items(i)
                details($"A{row}").Value = item.SKU
                details($"B{row}").Value = item.Name
                details($"C{row}").Value = item.Quantity
                ' Highlight low stock items
                If item.Quantity < item.ReorderLevel Then
                    details($"C{row}").Style.BackgroundColor = "#FFB6B6"
                End If
            Next
            Using stream = workbook.ToStream()
                Return stream.ToArray()
            End Using
        End Function
    End Class
End Namespace