C#通过NPOI读取写出及打印excel

写出xlsx

//创建一个工作簿对象
            XSSFWorkbook wb = new XSSFWorkbook();
            //插入指定名称的工作表
            ISheet sheet = wb.CreateSheet("mysheet");
            //插入指定行，在此行对象上创建单元格，并写入内容
            IRow row = sheet.CreateRow(2);  //参数为工作表的行号
            for (int i = 0; i < 10; i++)
            {
                ICell cell = row.CreateCell(i);
                cell.SetCellValue(i);
            }
            //定义一个文件流对象，将工作簿对象保存为Excel文件
            FileStream fs = new FileStream("test.xlsx", FileMode.OpenOrCreate, FileAccess.ReadWrite);
            wb.Write(fs);
            fs.Close(); fs.Dispose();

读取xlsx

FileStream fs = new FileStream("test.xlsx", FileMode.Open, FileAccess.Read);
//创建工作簿对象
XSSFWorkbook wb = new XSSFWorkbook(fs);
ISheet sheet = wb.GetSheet("mysheet");
IRow row = sheet.GetRow(2);
Console.WriteLine(row.GetCell(1));

    //Cell representing that column or null if undefined.
    ICell GetCell(int cellnum);

使用DataTable保存读取的表

DataTable dt = new DataTable();


            //指定excel所在路径
            string excelPath = path;


            //以文件流读取excel文件
            FileStream fs = new FileStream(excelPath, FileMode.Open, FileAccess.Read);
            //Offic2007以上
            IWorkbook workbook = new XSSFWorkbook(fs);
            //Offic2007以下
            if (excelPath.ToLower().EndsWith(".xls"))
            {
                workbook = new XSSFWorkbook(fs);
            }


            //取第一个sheet页的数据
            ISheet sheet = workbook.GetSheetAt(0);


            //获取第一行数据
            IRow firstRow = sheet.GetRow(0);
            //获取第一行中数据列的数量
            int columnCount = firstRow.LastCellNum;
            for (int i = firstRow.FirstCellNum; i <= columnCount; i++)
            {
                //获取单元格
                ICell cell = firstRow.GetCell(i);
                if (cell != null)
                {
                    //将第一行数据作为表头
                    string cellValue = cell.StringCellValue;
                    if (!string.IsNullOrEmpty(cellValue))
                    {
                        dt.Columns.Add(cellValue);
                    }
                }
            }
            //获取数据行的数量
            int rowCount = sheet.LastRowNum;
            for (int i = 1; i <= rowCount; i++)
            {
                //获取行
                IRow row = sheet.GetRow(i);
                if (row == null) continue;
                DataRow dataRow = dt.NewRow();
                for (int j = row.FirstCellNum; j <= dt.Columns.Count; j++)
                {
                    if (row.GetCell(j) != null)
                    {
                        //这里减FirstCellNum可以去除空白列数据
                        dataRow[j - row.FirstCellNum] = row.GetCell(j).ToString();
                    }


                }
                dt.Rows.Add(dataRow);
            }
            //资源释放
            workbook.Close();

全部代码

using System;
using System.Data;
using System.IO;            //提供文件流文件和文件流操作所需类
using NPOI.SS.UserModel;    //提供ISheet、IRow、ICell等接口
using NPOI.XSSF.UserModel;  //提供相关类操作扩展名为xlsx的2007之后版本Excel文件

namespace TestMpoi
{
    class MmyExcel
    {
        //创建一个新Excel文件并导出
        public void CreateExcel()
        {
            //创建一个工作簿对象
            XSSFWorkbook wb = new XSSFWorkbook();
            //插入指定名称的工作表
            ISheet sheet = wb.CreateSheet("mysheet");
            //插入指定行，在此行对象上创建单元格，并写入内容
            IRow row = sheet.CreateRow(2);  //参数为工作表的行号
            for (int i = 0; i < 10; i++)
            {
                ICell cell = row.CreateCell(i);
                cell.SetCellValue(i);
            }
            //定义一个文件流对象，将工作簿对象保存为Excel文件
            FileStream fs = new FileStream("test.xlsx", FileMode.OpenOrCreate, FileAccess.ReadWrite);
            wb.Write(fs);
            fs.Close(); fs.Dispose();
        }
        //打开已有Excel文件，修改内容后再导出
        public void OpenExcel()
        {
            FileStream fs = new FileStream("test.xlsx", FileMode.Open, FileAccess.Read);
            //创建工作簿对象
            XSSFWorkbook wb = new XSSFWorkbook(fs);
            ISheet sheet = wb.GetSheet("mysheet");
            IRow row = sheet.GetRow(2);
            Console.WriteLine(row.GetCell(1));
            fs.Close(); fs.Dispose();
            //根据工作表名获取工作簿对象，也可通过索引获取工作表wb.GetSheetAt(int index)
            // ISheet sheet = wb.GetSheet("mysheet");
            // //更改指定单元格内容，如果该单元格为null则会引发异常，需要对指定行和单元格进行判断
            // //sheet.GetRow(3).Cells[2].SetCellValue("内容");    //假设修改内容的单元格不为null可以这样修改内容
            // IRow row = sheet.GetRow(3);
            // if(row==null) row=sheet.CreateRow(3);
            // ICell cell = row.GetCell(2);    //ICell cell=row.Cells[2];
            // if(cell==null) cell=row.CreateCell(2);
            // cell.SetCellValue("内容");
            // //定义一个文件流对象，将工作簿对象保存为Excel文件
            // //读取指定单元格内容：string str=cell.StringCellValue;
            // FileStream fs1 = new FileStream("test2.xlsx",FileMode.OpenOrCreate,FileAccess.ReadWrite);
            // wb.Write(fs1);
            // fs1.Close(); fs1.Dispose();
        }
        public DataTable readExcel(String path)
        {
            //实例化一个datatable用来存储数据
            DataTable dt = new DataTable();


            //指定excel所在路径
            string excelPath = path;


            //以文件流读取excel文件
            FileStream fs = new FileStream(excelPath, FileMode.Open, FileAccess.Read);
            //Offic2007以上
            IWorkbook workbook = new XSSFWorkbook(fs);
            //Offic2007以下
            if (excelPath.ToLower().EndsWith(".xls"))
            {
                workbook = new XSSFWorkbook(fs);
            }


            //取第一个sheet页的数据
            ISheet sheet = workbook.GetSheetAt(0);


            //获取第一行数据
            IRow firstRow = sheet.GetRow(0);
            //获取第一行中数据列的数量
            int columnCount = firstRow.LastCellNum;
            for (int i = firstRow.FirstCellNum; i <= columnCount; i++)
            {
                //获取单元格
                ICell cell = firstRow.GetCell(i);
                if (cell != null)
                {
                    //将第一行数据作为表头
                    string cellValue = cell.StringCellValue;
                    if (!string.IsNullOrEmpty(cellValue))
                    {
                        dt.Columns.Add(cellValue);
                    }
                }
            }
            //获取数据行的数量
            int rowCount = sheet.LastRowNum;
            for (int i = 1; i <= rowCount; i++)
            {
                //获取行
                IRow row = sheet.GetRow(i);
                if (row == null) continue;
                DataRow dataRow = dt.NewRow();
                for (int j = row.FirstCellNum; j <= dt.Columns.Count; j++)
                {
                    if (row.GetCell(j) != null)
                    {
                        //这里减FirstCellNum可以去除空白列数据
                        dataRow[j - row.FirstCellNum] = row.GetCell(j).ToString();
                    }


                }
                dt.Rows.Add(dataRow);
            }
            //资源释放
            workbook.Close();
            //显示到页面
            return dt;
        }
        public void PrintTable(DataTable table)
        {
            // print head
            PrintLine(12 * (table.Columns.Count+1));
            Console.Write(string.Format("{0,12}"," "));
            foreach (DataColumn col in table.Columns)
            {
                Console.Write(string.Format("{0,12}", col.Caption));
            }
            Console.Write("\n");
            PrintLine(12 * (table.Columns.Count+1), "=");

            // print rows
            for (int i = 0; i < table.Rows.Count; i++)
            {
                Console.Write(string.Format("{0,12}",i+1));
                for (int j = 0; j < table.Columns.Count; j++)
                {
                    Console.Write(string.Format("{0,12}", table.Rows[i][j].ToString()));
                }
                Console.Write("\n");
            }
            PrintLine(12 * (table.Columns.Count+1));
        }

        /// 

        /// Print a line with specific char on to the console
        /// 
        /// count of the char to be printed
        /// the char to be printed, default is "="
        private void PrintLine(int length, string lineChar = "-")
        {
            string line = string.Empty;
            for (int i = 0; i < length; i++)
            {
                line += lineChar;
            }
            Console.WriteLine(line);
        }
    }
}

program.cs

using System;
using System.Data;
using TestMpoi;
namespace helloworld
{
    class Program
    {
        static void Main(string[] args)
        {
			MmyExcel excel_hhh = new MmyExcel();
            excel_hhh.CreateExcel();
            excel_hhh.OpenExcel();
            DataTable table = new DataTable();
            table = excel_hhh.readExcel("./test1.xlsx");
            excel_hhh.PrintTable(table);

        }
    }
}