Npoi

/************************************************************************
* Copyright (c) 2019 All Rights Reserved.
*创建人：wyh
*创建时间：2019-04-01 13:26:43
*描述
*=======================================================================
*修改标记
*修改时间：2019-04-01 13:26:43
*修改人：wyh
*描述：
************************************************************************/
using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;

namespace lmsHTETest
{
    public class ExcelHelper : IDisposable
    {
        private string fileName = null; //文件名
        private IWorkbook workbook = null;
        private FileStream fs = null;
        private bool disposed;
        

        public ExcelHelper(string fileName)
        {
            this.fileName = fileName;
            disposed = false;
        }

        /// <summary>
        /// 将DataTable数据导入到excel中
        /// </summary>
        /// <param name="data">要导入的数据</param>
        /// <param name="isColumnWritten">DataTable的列名是否要导入</param>
        /// <param name="sheetName">要导入的excel的sheet的名称</param>
        /// <returns>导入数据行数(包含列名那一行)</returns>
//        public int DataTableToExcel(DataTable data, string sheetName, bool isColumnWritten)
//        {
            public  bool DataTableToExcel(DataTable dt,string sheetname)
            {
                bool result = false;
                IWorkbook workbook = null;
                FileStream fs = null;
                IRow row = null;
                ISheet sheet = null;
                ICell cell = null;
                try
                {
                    if (dt != null && dt.Rows.Count > 0)
                    {
                        workbook = new HSSFWorkbook();
                        sheet = workbook.CreateSheet(sheetname);//创建一个名称为Sheet0的表  
                        int rowCount = dt.Rows.Count;//行数  
                        int columnCount = dt.Columns.Count;//列数  

                    //设置列头  
                    //row = sheet.CreateRow(0);//excel第一行设为列头  
                    //for (int c = 0; c < columnCount; c++)
                        //{
                        //    cell = row.CreateCell(c);
                        //    cell.SetCellValue(dt.Columns[c].ColumnName);
                        //}

                        //设置每行每列的单元格,  
                        for (int i = 0; i < rowCount; i++)
                        {
                            row = sheet.CreateRow(i + 1);
                            for (int j = 0; j < columnCount; j++)
                            {
                                cell = row.CreateCell(j);//excel第二行开始写入数据  
                                cell.SetCellValue(dt.Rows[i][j].ToString());
                            }
                        }
                        using (fs = File.OpenWrite(@"D:/myxls.xls"))
                        {
                            workbook.Write(fs);//向打开的这个xls文件中写入数据  
                            result = true;
                        }
                    }
                    return result;
                }
                catch (Exception ex)
                {
                    if (fs != null)
                    {
                        fs.Close();
                    }
                    return false;
                }
            }

        /// <summary>
        /// 将excel中的数据导入到DataTable中
        /// </summary>
        /// <param name="sheetName">excel工作薄sheet的名称</param>
        /// <param name="isFirstRowColumn">第一行是否是DataTable的列名</param>
        /// <returns>返回的DataTable</returns>
        public DataTable ExcelToDataTable(string sheetName, bool isFirstRowColumn)
        {
            ISheet sheet = null;
            DataTable data = new DataTable();
            int startRow = 0;
            try
            {
                fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
                if (fileName.IndexOf(".xlsx") > 0) // 2007版本
                    workbook = new XSSFWorkbook(fs);
                else if (fileName.IndexOf(".xls") > 0) // 2003版本
                    workbook = new HSSFWorkbook(fs);

                if (sheetName != null)
                {
                    sheet = workbook.GetSheet(sheetName);
                    if (sheet == null) //如果没有找到指定的sheetName对应的sheet，则尝试获取第一个sheet
                    {
                        sheet = workbook.GetSheetAt(0);
                    }
                }
                else
                {
                    sheet = workbook.GetSheetAt(0);
                }
                if (sheet != null)
                {
                    IRow firstRow = sheet.GetRow(0);
                    int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数

                    if (isFirstRowColumn)
                    {
                        for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
                        {
                            ICell cell = firstRow.GetCell(i);
                            if (cell != null)
                            {
                                string cellValue = cell.StringCellValue;
                                if (cellValue != null)
                                {
                                    DataColumn column = new DataColumn(cellValue);
                                    data.Columns.Add(column);
                                }
                            }
                        }
                        startRow = sheet.FirstRowNum + 1;
                    }
                    else
                    {
                        startRow = sheet.FirstRowNum;
                    }

                    //最后一列的标号
                    int rowCount = sheet.LastRowNum;
                    for (int i = startRow; i <= rowCount; ++i)
                    {
                        IRow row = sheet.GetRow(i);
                        if (row == null) continue; //没有数据的行默认是null　　　　　　　

                        DataRow dataRow = data.NewRow();
                        
                        for (int j = row.FirstCellNum; j < cellCount; ++j)
                        {
                            if (row.FirstCellNum != -1)
                            {
                                if (row.GetCell(j) != null)
                                {
                                    if (row.GetCell(j).CellType == CellType.Formula &&row.GetCell(j).ColumnIndex ==5)
                                    {
                                        row.GetCell(j).SetCellType(CellType.String);
                                        dataRow[j] = Math.Round(decimal.Parse(row.GetCell(j).StringCellValue),2);
                                    }
                                    else
                                    {
                                        dataRow[j] = row.GetCell(j).ToString();
                                    }
                                } //同理，没有数据的单元格都默认是null
                                    
                            }
                            
                        }
                        data.Rows.Add(dataRow);
                    }
                }

                return data;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception: " + ex.Message);
                return null;
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!this.disposed)
            {
                if (disposing)
                {
                    if (fs != null)
                        fs.Close();
                }

                fs = null;
                disposed = true;
            }
        }
    }
}

使用

using (ExcelHelper excelHelper = new ExcelHelper(FileName))
                {
                    excellist = excelHelper.ExcelToDataTable("正误名单", true);
                }
                var ccount = excellist.Columns.Count;
                var rcount = excellist.Rows.Count;
                var str = "";
                var j = 0;
                for (int i = 0; i < rcount; i+=j)
                {
                    var strexerciseid = excellist.Rows[i][0].ToString();
                }