操作Excel是一个比较常见的业务场景，本篇将使用EPPlus简单演示一个导入导出的示例。

EPPlus开源地址：https://github.com/EPPlusSoftware/EPPlus

在项目中添加EPPlus组件

Install-Package EPPlus

导入

先准备一个Excel文件，将其内容读取出来，并序列化成JSON字符串进行返回。

[HttpPost]

public List<ExcelDemoDto> Import([FromForm] ImportExcelInput input)

{

    var list = new List<ExcelDemoDto>();

    using (var package = new ExcelPackage(input.ExcelFile.OpenReadStream()))

    {

        // 获取到第一个Sheet，也可以通过 Worksheets["name"] 获取指定的工作表

        var sheet = package.Workbook.Worksheets.First();

        #region 获取开始和结束行列的个数，根据个数可以做各种校验工作

        // +1 是因为第一行往往我们获取到的都是Excel的标题

        int startRowNumber = sheet.Dimension.Start.Row + 1;

        int endRowNumber = sheet.Dimension.End.Row;

        int startColumn = sheet.Dimension.Start.Column;

        int endColumn = sheet.Dimension.End.Column;

        #endregion

        // 循环获取整个Excel数据表数据

        for (int currentRow = startRowNumber; currentRow <= endRowNumber; currentRow++)

        {

            list.Add(new ExcelDemoDto

            {

                AAA = sheet.Cells[currentRow, 1].Text,

                BBB = sheet.Cells[currentRow, 2].Text,

                CCC = sheet.Cells[currentRow, 3].Text,

                DDD = sheet.Cells[currentRow, 4].Text,

                EEE = sheet.Cells[currentRow, 5].Text,

                FFF = sheet.Cells[currentRow, 6].Text

            });

        }

    }

    return list;

}

public class ExcelDemoDto

{

    public string AAA { get; set; }

    public string BBB { get; set; }

    public string CCC { get; set; }

    public string DDD { get; set; }

    public string EEE { get; set; }

    public string FFF { get; set; }

}

public class ImportExcelInput

{

    public IFormFile ExcelFile { get; set; }

}

导出

[HttpGet]

public async Task<string> Export()

{

    using var package = new ExcelPackage();

    var worksheet = package.Workbook.Worksheets.Add("sheet1");

    var headers = new string[] { "AAA", "BBB", "CCC", "DDD", "EEE", "FFF" };

    for (int i = 0; i < headers.Length; i++)

    {

        worksheet.Cells[1, i + 1].Value = headers[i];

        worksheet.Cells[1, i + 1].Style.Font.Bold = true;

    }

    // 模拟数据

    var list = new List<ExcelDemoDto>();

    for (int i = 1; i <= 10; i++)

    {

        list.Add(new ExcelDemoDto

        {

            AAA = $"A{i}",

            BBB = $"B{i}",

            CCC = $"C{i}",

            DDD = $"D{i}",

            EEE = $"E{i}",

            FFF = $"F{i}"

        });

    }

    // 支持各种直接获取数据的方法

    // worksheet.Cells.Load*...

    int row = 2;

    foreach (var item in list)

    {

        worksheet.Cells[row, 1].Value = item.AAA;

        worksheet.Cells[row, 2].Value = item.BBB;

        worksheet.Cells[row, 3].Value = item.CCC;

        worksheet.Cells[row, 4].Value = item.DDD;

        worksheet.Cells[row, 5].Value = item.EEE;

        worksheet.Cells[row, 6].Value = item.FFF;

        row++;

    }

    // 通常做法是，将excel上传至对象存储，获取到下载链接，这里将其输出到项目根目录。

    var path = Path.Combine(Directory.GetCurrentDirectory(), $"excel.xlsx");

    await package.GetAsByteArray().DownloadAsync(path);

    return path;

}