在.NET C# 中下载 Excel 文件：将数据导出为 XLSX、CSV 等格式

using IronXL;
using Microsoft.AspNetCore.Mvc;
public class ReportController : Controller
{
    // Export employee data as a downloadable Excel file
    public IActionResult DownloadExcel()
    {
        // Create a new workbook and worksheet
        var workbook = WorkBook.Create(ExcelFileFormat.XLSX);
        var worksheet = workbook.CreateWorkSheet("Employees");
        // Add header row with column names
        worksheet["A1"].Value = "Name";
        worksheet["B1"].Value = "Department";
        worksheet["C1"].Value = "Salary";
        // Populate cells with data values
        worksheet["A2"].Value = "Alice Torres";
        worksheet["B2"].Value = "Engineering";
        worksheet["C2"].Value = 95000;
        worksheet["A3"].Value = "James Park";
        worksheet["B3"].Value = "Marketing";
        worksheet["C3"].Value = 78000;
        // Export workbook to a MemoryStream for download
        var stream = workbook.ToStream();
        string filename = "Employees.xlsx";
        var content = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
        // Return file to the browser with content disposition attachment
        return File(stream, content, filename);
    }
}

Imports IronXL
Imports Microsoft.AspNetCore.Mvc

Public Class ReportController
    Inherits Controller

    ' Export employee data as a downloadable Excel file
    Public Function DownloadExcel() As IActionResult
        ' Create a new workbook and worksheet
        Dim workbook = WorkBook.Create(ExcelFileFormat.XLSX)
        Dim worksheet = workbook.CreateWorkSheet("Employees")
        ' Add header row with column names
        worksheet("A1").Value = "Name"
        worksheet("B1").Value = "Department"
        worksheet("C1").Value = "Salary"
        ' Populate cells with data values
        worksheet("A2").Value = "Alice Torres"
        worksheet("B2").Value = "Engineering"
        worksheet("C2").Value = 95000
        worksheet("A3").Value = "James Park"
        worksheet("B3").Value = "Marketing"
        worksheet("C3").Value = 78000
        ' Export workbook to a MemoryStream for download
        Dim stream = workbook.ToStream()
        Dim filename As String = "Employees.xlsx"
        Dim content = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
        ' Return file to the browser with content disposition attachment
        Return File(stream, content, filename)
    End Function
End Class

using IronXL;
using Microsoft.AspNetCore.Mvc;
public class DataExportController : Controller
{
    // Export database records to an xlsx file for download
    public IActionResult ExportDatabaseReport()
    {
        // Simulate a database query returning order records
        var orders = new[]
        {
            new { OrderId = 1001, Customer = "Acme Corp", Total = 4500.00m },
            new { OrderId = 1002, Customer = "Globex Inc", Total = 12300.50m },
            new { OrderId = 1003, Customer = "Initech LLC", Total = 890.75m },
        };
        var workbook = WorkBook.Create(ExcelFileFormat.XLSX);
        var worksheet = workbook.CreateWorkSheet("Orders");
        // Write headers
        worksheet["A1"].Value = "Order ID";
        worksheet["B1"].Value = "Customer";
        worksheet["C1"].Value = "Total";
        // Write each row of data from the query results
        for (int i = 0; i < orders.Length; i++)
        {
            int row = i + 2;
            worksheet[$"A{row}"].Value = orders[i].OrderId;
            worksheet[$"B{row}"].Value = orders[i].Customer;
            worksheet[$"C{row}"].Value = orders[i].Total;
        }
        var stream = workbook.ToStream();
        string filename = $"OrderReport-{DateTime.Now:yyyyMMdd}.xlsx";
        return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", filename);
    }
}

Imports IronXL
Imports Microsoft.AspNetCore.Mvc

Public Class DataExportController
    Inherits Controller

    ' Export database records to an xlsx file for download
    Public Function ExportDatabaseReport() As IActionResult
        ' Simulate a database query returning order records
        Dim orders = New() {
            New With {.OrderId = 1001, .Customer = "Acme Corp", .Total = 4500.0D},
            New With {.OrderId = 1002, .Customer = "Globex Inc", .Total = 12300.5D},
            New With {.OrderId = 1003, .Customer = "Initech LLC", .Total = 890.75D}
        }
        Dim workbook = WorkBook.Create(ExcelFileFormat.XLSX)
        Dim worksheet = workbook.CreateWorkSheet("Orders")
        ' Write headers
        worksheet("A1").Value = "Order ID"
        worksheet("B1").Value = "Customer"
        worksheet("C1").Value = "Total"
        ' Write each row of data from the query results
        For i As Integer = 0 To orders.Length - 1
            Dim row As Integer = i + 2
            worksheet($"A{row}").Value = orders(i).OrderId
            worksheet($"B{row}").Value = orders(i).Customer
            worksheet($"C{row}").Value = orders(i).Total
        Next
        Dim stream = workbook.ToStream()
        Dim filename As String = $"OrderReport-{DateTime.Now:yyyyMMdd}.xlsx"
        Return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", filename)
    End Function
End Class

using IronXL;
using Microsoft.AspNetCore.Mvc;
public class CsvController : Controller
{
    // Export data as a CSV file download
    public IActionResult ExportCsv()
    {
        var workbook = WorkBook.Create(ExcelFileFormat.XLSX);
        var worksheet = workbook.CreateWorkSheet("Products");
        worksheet["A1"].Value = "SKU";
        worksheet["B1"].Value = "Product";
        worksheet["C1"].Value = "Price";
        worksheet["A2"].Value = "WDG-001";
        worksheet["B2"].Value = "Widget Pro";
        worksheet["C2"].Value = 29.99;
        // Convert to CSV stream instead of XLSX
        var stream = workbook.ToCsvStream();
        string filename = "Products.csv";
        return File(stream, "text/csv", filename);
    }
}

Imports IronXL
Imports Microsoft.AspNetCore.Mvc

Public Class CsvController
    Inherits Controller

    ' Export data as a CSV file download
    Public Function ExportCsv() As IActionResult
        Dim workbook = WorkBook.Create(ExcelFileFormat.XLSX)
        Dim worksheet = workbook.CreateWorkSheet("Products")
        worksheet("A1").Value = "SKU"
        worksheet("B1").Value = "Product"
        worksheet("C1").Value = "Price"
        worksheet("A2").Value = "WDG-001"
        worksheet("B2").Value = "Widget Pro"
        worksheet("C2").Value = 29.99
        ' Convert to CSV stream instead of XLSX
        Dim stream = workbook.ToCsvStream()
        Dim filename As String = "Products.csv"
        Return File(stream, "text/csv", filename)
    End Function
End Class

public IActionResult ConvertUpload(IFormFile upload)
{
    using var memoryStream = new MemoryStream();
    upload.CopyTo(memoryStream);
    memoryStream.Position = 0;
    // Load uploaded Excel file from the stream
    var workbook = WorkBook.Load(memoryStream);
    // Re-export as XLSX regardless of the original file extension or file type
    var stream = workbook.ToXlsxStream();
    string filename = Path.GetFileNameWithoutExtension(upload.FileName) + ".xlsx";
    return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", filename);
}

Imports Microsoft.AspNetCore.Mvc
Imports System.IO

Public Function ConvertUpload(upload As IFormFile) As IActionResult
    Using memoryStream As New MemoryStream()
        upload.CopyTo(memoryStream)
        memoryStream.Position = 0
        ' Load uploaded Excel file from the stream
        Dim workbook = WorkBook.Load(memoryStream)
        ' Re-export as XLSX regardless of the original file extension or file type
        Dim stream = workbook.ToXlsxStream()
        Dim filename As String = Path.GetFileNameWithoutExtension(upload.FileName) & ".xlsx"
        Return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", filename)
    End Using
End Function