本文利用第三方开源库NPOI实现Excel97-2003，Excel2007+的数据导入导出操作。不依赖Office是否安装。NPOI开源项目地址：http://npoi.codeplex.com/。

库文件下载：http://npoi.codeplex.com/releases/view/115353

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Reflection;
using System.Text;
using System.Windows.Forms;
using NPOI.HPSF;
using NPOI.HSSF.UserModel;
using NPOI.HSSF.Util;
using NPOI.SS.UserModel;
using NPOI.SS.Util;
using NPOI.XSSF.UserModel;
using NPOI.XSSF.Util;

namespace Youwei.Common
{
    /// <summary>
    /// Excel操作类。利用第三方开源库NPOI实现Excel97-2003，Excel2007+的数据导入导出操作。不依赖Office是否安装。
    /// NPOI开源项目地址：http://npoi.codeplex.com/
    /// </summary>
    public class ExcelHelper
    {
        private static String FilterExcel = "Excel文件 (*.xls;*.xlsx)|*.xls;*.xlsx";

        /// <summary>
        /// 从网格将数据导出到Excel，支持Excel97-2003(.xls)、Excel2007+(.xlsx)
        /// </summary>
        /// <param name="dgv">网格</param>
        /// <param name="ignoredColumns">要忽略导出的列名称集合</param>
        /// <param name="fileName">导出到的文件名。为空时将弹出保存对话框</param>
        public static void ExportToExcel(DataGridView dgv,List<string> ignoredColumns = null,string fileName = "")
        {
            if (String.IsNullOrEmpty(fileName))
                fileName = Dialog.SaveFileDialog(FilterExcel);

            if (String.IsNullOrEmpty(fileName))
                return;

            bool isSuccess = false;
            IWorkbook workBook = null;
            ISheet sheet = null;
            IRow dataRow = null;
            try
            {
                //不同格式实例化不同工作薄
                if (fileName.EndsWith(".xls"))
                    workBook = new HSSFWorkbook();
                else if (fileName.EndsWith(".xlsx"))
                    workBook = new XSSFWorkbook();

                sheet = workBook.CreateSheet();
                dataRow = sheet.CreateRow(0);

                //表头样式
                ICellStyle headerStyle = workBook.CreateCellStyle();
                headerStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
                headerStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
                headerStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
                headerStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;

                headerStyle.BottomBorderColor = NPOI.HSSF.Util.HSSFColor.Black.Index;
                headerStyle.LeftBorderColor = HSSFColor.Black.Index;
                headerStyle.RightBorderColor = HSSFColor.Black.Index;
                headerStyle.TopBorderColor = HSSFColor.Black.Index;

                IFont font = workBook.CreateFont();
                font.FontHeightInPoints = 10;
                font.Boldweight = 700;
                headerStyle.SetFont(font);
                headerStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;


                int i = 0,j = 0;
                int ignoreCnt = 0;
                //填充表头
                for (i = 0; i < dgv.Columns.Count; i++)
                {
                    if ((ignoredColumns != null && ignoredColumns.Contains(dgv.Columns[i].Name)) || !dgv.Columns[i].Visible || string.IsNullOrEmpty(dgv.Columns[i].HeaderText))
                    {
                        ignoreCnt++;
                        continue;
                    }
                    dataRow.CreateCell(i - ignoreCnt).SetCellValue(dgv.Columns[i].HeaderText);
                    dataRow.Cells[i - ignoreCnt].CellStyle = headerStyle;
                }

                //内容样式
                ICellStyle cellStyle = headerStyle;
                cellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Left;
                font = workBook.CreateFont();
                font.FontHeightInPoints = 10;
                font.Boldweight = 100;
                cellStyle.SetFont(font);

                //填充内容
                DataGridViewCell cell = null;
                for (i = 0; i < dgv.Rows.Count; i++)
                {
                    dataRow = sheet.CreateRow(i + 1);
                    ignoreCnt = 0;
                    for (j = 0; j < dgv.Columns.Count; j++)
                    {
                        if ((ignoredColumns != null && ignoredColumns.Contains(dgv.Columns[j].Name)) || !dgv.Columns[j].Visible || string.IsNullOrEmpty(dgv.Columns[j].HeaderText))
                        {
                            ignoreCnt++;
                            continue;
                        }
                        cell = dgv[j,i];
                        if (cell is DataGridViewComboBoxCell)
                            dataRow.CreateCell(j - ignoreCnt).SetCellValue(ConvertHelper.ToString(cell.FormattedValue));
                        else
                            dataRow.CreateCell(j - ignoreCnt).SetCellValue(ConvertHelper.ToString(cell.Value));
                        dataRow.Cells[j - ignoreCnt].CellStyle = cellStyle;
                    }
                }

                //写文件
                using (MemoryStream ms = new MemoryStream())
                {
                    using (FileStream fs = new FileStream(fileName,FileMode.Create,FileAccess.Write))
                    {
                        workBook.Write(ms);
                        ms.Flush();
                        ms.Position = 0;
                        byte[] data = ms.ToArray();
                        fs.Write(data,data.Length);
                        fs.Flush();
                        data = null;
                        isSuccess = true;
                    }
                }

                //打开文件
                if (isSuccess && Dialog.Confirm("数据已经导出到Excel成功，你要打开吗？") == DialogResult.Yes)
                {
                    Util.OpenFile(fileName);
                }
            }
            catch (Exception ex)
            {
                Dialog.Error(ex,System.Reflection.MethodBase.GetCurrentMethod(),true);
            }
            finally
            {
                if (dataRow != null)
                    dataRow = null;

                if (sheet != null)
                    sheet = null;

                if (workBook != null)
                {
                    workBook.Clear();
                    workBook = null;
                }
            }
        }

        /// <summary>
        /// 从Excel导入数据到实体类集合。支持Excel97-2003(.xls)、Excel2007+(.xlsx)
        /// </summary>
        /// <typeparam name="T">实体类</typeparam>
        /// <param name="fileName">要导入的Excel文件名。为空时将弹出保存对话框</param>
        /// <param name="propertyTextNamePair">实体类属性的名称及属性名对应键值对</param>
        /// <param name="startSheet">导入的起始Excel表单序号</param>
        /// <param name="startRow">导入的起始Excel行号</param>
        /// <param name="startColumn">导入的起始Excel列号</param>
        /// <returns>泛型实体类集合</returns>
        public static List<T> ImportFromExcel<T>(string fileName,Dictionary<string,string> propertyTextNamePair,int startSheet = 0,int startRow = 0,int startColumn = 0) where T : new()
        {
            List<T> list = new List<T>();
            if (String.IsNullOrEmpty(fileName) || !System.IO.File.Exists(fileName))
                fileName = Dialog.OpenFileDialog(FilterExcel);

            if (String.IsNullOrEmpty(fileName) || !System.IO.File.Exists(fileName))
                return list;

            IWorkbook workBook = null;
            ISheet sheet = null;
            IRow row = null;

            try
            {
                //加载文档
                using (FileStream fileStream = new FileStream(fileName,FileMode.Open))
                {
                    //不同格式实例化不同工作薄
                    if (fileName.EndsWith(".xls"))
                        workBook = new HSSFWorkbook(fileStream);
                    else if (fileName.EndsWith(".xlsx"))
                        workBook = new XSSFWorkbook(fileStream);
                }

                //加载指定工作薄
                sheet = workBook.GetSheetAt(startSheet);
                //workBook.NumberOfSheets //工作薄的表单数

                //加载表头
                IRow headerRow = sheet.GetRow(startRow);
                ICell cellHeader = null;
                ICell cell = null;
                int cellCount = headerRow.LastCellNum;

                //获取实体类属性
                Type type = typeof(T);
                PropertyInfo[] ps = type.GetProperties();
                T t = default(T);
                PropertyInfo p = null;

                //遍历行列，赋值到实体类，并添加到实体类集合
                for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++)
                {
                    row = sheet.GetRow(i);
                    t = new T();
                    for (int j = 0; j < cellCount; j++)
                    {
                        cellHeader = headerRow.GetCell(j);
                        cell = row.GetCell(j);

                        if (propertyTextNamePair != null && propertyTextNamePair.ContainsKey(cellHeader.ToString()))
                            p = type.GetProperty(propertyTextNamePair[cellHeader.ToString()]);
                        else
                            p = type.GetProperty(cellHeader.ToString());

                        if (p != null)
                            p.SetValue(t,Convert.ChangeType(cell.ToString(),p.PropertyType),null);
                    }
                    list.Add(t);
                }

                //回收资源
                ps = null;
                cellHeader = null;
                headerRow = null;
            }
            catch (Exception ex)
            {
                Dialog.Error(ex,true);
            }
            finally
            {
                if (row != null)
                    row = null;

                if (sheet != null)
                    sheet = null;

                if (workBook != null)
                {
                    workBook.Clear();
                    workBook = null;
                }
            }

            return list;
        }
    }
}