ASP.NETCore -----导出Excel文件并下载

本事例分为nopi(安装DotNetCore.NPOI)下载和EPPlus(EPPlus.Core.dll)下载，其中npoi下载演示的是根据执行的模板进行数据下载

npoi帮助类NpoiExcelUtility

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Threading.Tasks;

namespace ASPNETCoreExcel
{
    public class NpoiExcelUtility
    {
        private string _xlsPath = string.Empty;
        private HSSFWorkbook _workBook = null;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="xlsPath">xls保存路径</param>
        /// <param name="TempletFileName">xls模板路径</param>
        public NpoiExcelUtility(string xlsPath, string TempletFileName)
        {
            _xlsPath = this.CheckFilePath(xlsPath);

            FileStream file = new FileStream(TempletFileName, FileMode.Open, FileAccess.Read);
            _workBook = new HSSFWorkbook(file);
        }

        /// <summary>
        /// 将DataTable保存到sheet里
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="sheet"></param>
        private void DataTableToExcel(DataTable dt, ISheet sheet)
        {
            ICellStyle style = _workBook.CreateCellStyle();
            style.Alignment = HorizontalAlignment.Left;
            style.VerticalAlignment = VerticalAlignment.Center;

            ICellStyle colStyle = _workBook.CreateCellStyle();
            colStyle.Alignment = HorizontalAlignment.Left;
            colStyle.VerticalAlignment = VerticalAlignment.Center;
            IFont font = _workBook.CreateFont();
            font.Color = NPOI.HSSF.Util.HSSFColor.LightBlue.Index;
            colStyle.SetFont(font);

            //列名
            //IRow row = sheet.CreateRow(0);
            //for (int i = 0; i < dt.Columns.Count; i++)
            //{
            //    sheet.SetDefaultColumnStyle(i, style);

            //    ICell cell = row.CreateCell(i);
            //    cell.SetCellValue(dt.Columns[i].ToString());

            //    cell.CellStyle = colStyle;
            //}
            //内容
            var headerRow = (HSSFRow)sheet.GetRow();

            for (int i = ; i <= dt.Rows.Count; i++)
            {
                IRow row = sheet.CreateRow(i + );
                row.Height =  * ;
                ICell numcell = row.CreateCell();
                numcell.SetCellValue(i);
                for (int j = ; j < dt.Columns.Count; j++)
                {
                    object obj = dt.Rows[i - ][j];
                    if (obj != null)
                    {
                        string ColumnName = dt.Columns[j].ToString();
                        var _Column = headerRow.Cells.Find(t => !string.IsNullOrEmpty(t.StringCellValue) && t.ToString().ToLower() == ColumnName.ToLower());
                        //ICell cell = row.CreateCell(j + 1);
                        if (_Column != null)
                        {
                            ICell cell = row.CreateCell(_Column.ColumnIndex);
                            if (obj is double || obj is float || obj is int || obj is long || obj is decimal)
                            {
                                cell.SetCellValue(Convert.ToDouble(obj));
                            }
                            else if (obj is bool)
                            {
                                cell.SetCellValue((bool)obj);
                            }
                            else
                            {
                                cell.SetCellValue(obj.ToString());
                            }
                        }
                    }
                }
            }
        }

        /// <summary>
        /// 保存Excel
        /// </summary>
        public void SaveExcel()
        {
            FileStream file = new FileStream(_xlsPath, FileMode.Create);
            _workBook.Write(file);
            file.Close();
        }

        /// <summary>
        /// 创建Sheet
        /// </summary>
        /// <param name="sheetName">sheet名称</param>
        /// <param name="tbl">DataTable数据表，当行数大于65536时，自动分割成几个sheet，sheet名称为sheetName_i</param>
        public void CreatExcelSheet(string sheetName, DataTable tbl)
        {
            string sName = this.CheckSheetName(sheetName);

            int rowMax = ;
            int intNum = tbl.Rows.Count / rowMax;
            int remainder = tbl.Rows.Count % rowMax;

            for (int i = ; i < intNum; i++)
            {
                DataTable subTbl = tbl.Clone();
                for (int j = ; j < ; j++)
                {
                    int rowIndex = i * rowMax + j;
                    subTbl.Rows.Add(tbl.Rows[rowIndex].ItemArray);
                }
                string subSheet = sName + "_" + (i + );
                //ISheet sheet = _workBook.CreateSheet(subSheet);
                ISheet sheet = _workBook.GetSheetAt();
                this.DataTableToExcel(subTbl, sheet);
            }
            if (remainder > )
            {
                DataTable subTbl = tbl.Clone();
                for (int j = ; j < remainder; j++)
                {
                    int rowIndex = intNum * rowMax + j;
                    subTbl.Rows.Add(tbl.Rows[rowIndex].ItemArray);
                }
                string subSheet = sName + "_" + (intNum + );
                if (intNum < )
                {
                    subSheet = sName;
                }
                //ISheet sheet = _workBook.CreateSheet(subSheet);
                ISheet sheet = _workBook.GetSheetAt();
                this.DataTableToExcel(subTbl, sheet);
            }
        }

        /// <summary>
        /// 检查sheet名称是否合法，并去掉不合法字符
        /// </summary>
        /// <param name="sheetName"></param>
        private string CheckSheetName(string sheetName)
        {
            string rlt = sheetName;
            string[] illegalChars = { "*", "?", "\"", @"\", "/" };
            for (int i = ; i < illegalChars.Length; i++)
            {
                rlt = rlt.Replace(illegalChars[i], "");
            }
            return rlt;
        }

        /// <summary>
        ///  检查xls路径是否合法，并去掉不合法字符
        /// </summary>
        /// <param name="filePath"></param>
        private string CheckFilePath(string filePath)
        {
            string dir = Path.GetDirectoryName(filePath);
            string fileName = Path.GetFileNameWithoutExtension(filePath);
            string ext = Path.GetExtension(filePath);

            string[] illegalChars = { ":", "*", "?", "\"", "<", ">", "|", @"\", "/" };
            for (int i = ; i < illegalChars.Length; i++)
            {
                fileName = fileName.Replace(illegalChars[i], "");
            }
            string rlt = Path.Combine(dir, fileName + ext);
            return rlt;
        }
    }
}

调用

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using ASPNETCoreExcel.Models;
using Microsoft.AspNetCore.Hosting;
using System.IO;
using OfficeOpenXml;
using System.Data;

namespace ASPNETCoreExcel.Controllers
{
    public class HomeController : Controller
    {
        private IHostingEnvironment _hostingEnvironment;

        public HomeController(IHostingEnvironment hostingEnvironment)
        {
            _hostingEnvironment = hostingEnvironment;
        }
        public IActionResult Index()
        {
            return View();
        }

        public IActionResult About()
        {
            ViewData["Message"] = "Your application description page.";

            return View();
        }

        public IActionResult Contact()
        {
            ViewData["Message"] = "Your contact page.";

            return View();
        }

        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
        /// <summary>
        /// 不根据指定模板进行导出excel下载(非npoi实现)
        /// </summary>
        /// <returns></returns>
        public IActionResult Export2()
        {
            string sWebRootFolder = _hostingEnvironment.WebRootPath;
            string sFileName = "部落.xlsx";

            FileInfo file = new FileInfo(Path.Combine(sWebRootFolder, sFileName));
            file.Delete();
            using (ExcelPackage package = new ExcelPackage(file))
            {
                // 添加worksheet
                ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("部落");
                //添加头
                worksheet.Cells[, ].Value = "ID";
                worksheet.Cells[, ].Value = "Name";
                worksheet.Cells[, ].Value = "Url";
                //添加值
                worksheet.Cells["A2"].Value = ;
                worksheet.Cells["B2"].Value = "For丨丶";
                worksheet.Cells["C2"].Value = "https://buluo.qq.com/p/barindex.html?bid=310072";

                worksheet.Cells["A3"].Value = ;
                worksheet.Cells["B3"].Value = "For丨丶Tomorrow";
                worksheet.Cells["C3"].Value = "https://buluo.qq.com/p/barindex.html?bid=310072";
                worksheet.Cells["C3"].Style.Font.Bold = true;
                package.Save();
            }
            return File(sFileName, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", sFileName);
        }

        /// <summary>
        /// 根据指定模板进行导出excel下载(npoi实现)
        /// </summary>

        public IActionResult Export()
        {
            var TempletFilePath = @"D:\谷歌下载\ASPNETCore操作Excel\ASPNETCoreExcel\Template";//模板地址
            var ExportFilePath = "D:";//导出后存放的地址
            string TempletFileName = string.Format("{0}\\调查表.xls", TempletFilePath);
            string ExportFileName = string.Format("{0}\\调查表_{1}.xls", ExportFilePath, DateTime.Now.ToString("yyyy年MM月dd日hh时mm分ss秒"));

            var _NpoiExcelUtility = new NpoiExcelUtility(ExportFileName, TempletFileName);
            #region 测试数据
            //创建DataTable
            DataTable dt = new DataTable("NewDt");

            //创建自增长的ID列
            DataColumn dc = dt.Columns.Add("id", Type.GetType("System.Int32"));
            dc.AutoIncrement = true;   //自动增加
            dc.AutoIncrementSeed = ;  //起始为1
            dc.AutoIncrementStep = ;  //步长为1
            dc.AllowDBNull = false;    //非空

            //创建其它列表
            dt.Columns.Add(new DataColumn("Name", Type.GetType("System.String")));

            //创建数据
            DataRow dr = dt.NewRow();
            dr["Name"] = "张三";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["Name"] = "李四";
            dt.Rows.Add(dr);
            dr = dt.NewRow();
            dr["Name"] = "王五";
            dt.Rows.Add(dr);
            #endregion
            _NpoiExcelUtility.CreatExcelSheet("调查表", dt);
            _NpoiExcelUtility.SaveExcel();
            var stream = System.IO.File.OpenRead(ExportFileName);//excel表转换成流
            return File(stream, "application/vnd.android.package-archive", Path.GetFileName(ExportFileName));//进行浏览器下载

        }

    }
}

前端界面

@{
    Layout = null;
}
<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Xlsx</title>
</head>
<body>
    <h2>ASP.NET Core 导出Excel xlsx 文件</h2>
    <a asp-action="Export">导出Excel</a>
</body>
</html>

代码下载