NPOI读写Excel

1、整个Excel表格叫做工作表：WorkBook（工作薄），包含的叫页（工作表）：Sheet；行：Row；单元格Cell。

2、NPOI是POI的C#版本，NPOI的行和列的index都是从0开始

3、POI读取Excel有两种格式一个是HSSF，另一个是XSSF。 HSSF和XSSF的区别如下：
HSSF is the POI Project's pure Java implementation of the Excel '97(-2007) file format.
XSSF is the POI Project's pure Java implementation of the Excel 2007 OOXML (.xlsx) file format.
即：HSSF适用2007以前的版本,XSSF适用2007版本及其以上的。

下面是用NPOI读写Excel的例子：ExcelHelper封装的功能主要是把DataTable中数据写入到Excel中，或者是从Excel读取数据到一个DataTable中。

 ExcelHelper类：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using NPOI.SS.UserModel;

using NPOI.XSSF.UserModel;

using NPOI.HSSF.UserModel;

using System.IO;

using System.Data;



namespace NetUtilityLib

{

    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)

        {

            int i = 0;

            int j = 0;

            int count = 0;

            ISheet sheet = null;



            fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);

            if (fileName.IndexOf(".xlsx") > 0) // 2007版本

                workbook = new XSSFWorkbook();

            else if (fileName.IndexOf(".xls") > 0) // 2003版本

                workbook = new HSSFWorkbook();



            try

            {

                if (workbook != null)

                {

                    sheet = workbook.CreateSheet(sheetName);

                }

                else

                {

                    return -1;

                }



                if (isColumnWritten == true) //写入DataTable的列名

                {

                    IRow row = sheet.CreateRow(0);

                    for (j = 0; j < data.Columns.Count; ++j)

                    {

                        row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);

                    }

                    count = 1;

                }

                else

                {

                    count = 0;

                }



                for (i = 0; i < data.Rows.Count; ++i)

                {

                    IRow row = sheet.CreateRow(count);

                    for (j = 0; j < data.Columns.Count; ++j)

                    {

                        row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());

                    }

                    ++count;

                }

                workbook.Write(fs); //写入到excel

                return count;

            }

            catch (Exception ex)

            {

                Console.WriteLine("Exception: " + ex.Message);

                return -1;

            }

        }



        /// <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.GetCell(j) != null) //同理，没有数据的单元格都默认是null

                                dataRow[j] = row.GetCell(j).ToString();

                        }

                        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;

            }

        }

    }

}

测试代码：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data;



namespace NPOIExcelExample

{

    class Program

    {

        static DataTable GenerateData()

        {

            DataTable data = new DataTable();

            for (int i = 0; i < 5; ++i)

            {

                data.Columns.Add("Columns_" + i.ToString(), typeof(string));

            }



            for (int i = 0; i < 10; ++i)

            {

                DataRow row = data.NewRow();

                row["Columns_0"] = "item0_" + i.ToString();

                row["Columns_1"] = "item1_" + i.ToString();

                row["Columns_2"] = "item2_" + i.ToString();

                row["Columns_3"] = "item3_" + i.ToString();

                row["Columns_4"] = "item4_" + i.ToString();

                data.Rows.Add(row);

            }

            return data;

        }



        static void PrintData(DataTable data)

        {

            if (data == null) return;

            for (int i = 0; i < data.Rows.Count; ++i)

            {

                for (int j = 0; j < data.Columns.Count; ++j)

                    Console.Write("{0} ", data.Rows[i][j]);

                Console.Write("\n");

            }

        }



        static void TestExcelWrite(string file)

        {

            try

            {

                using (ExcelHelper excelHelper = new ExcelHelper(file))

                {

                    DataTable data = GenerateData();

                    int count = excelHelper.DataTableToExcel(data, "MySheet", true);

                    if (count > 0)

                        Console.WriteLine("Number of imported data is {0} ", count);

                }

            }

            catch (Exception ex)

            {

                Console.WriteLine("Exception: " + ex.Message);

            }

        }



        static void TestExcelRead(string file)

        {

            try

            {

                using (ExcelHelper excelHelper = new ExcelHelper(file))

                {

                    DataTable dt = excelHelper.ExcelToDataTable("MySheet", true);

                    PrintData(dt);

                }

            }

            catch (Exception ex)

            {

                Console.WriteLine("Exception: " + ex.Message);

            }

        }



        static void Main(string[] args)

        {

            string file = "..\\..\\myTest.xlsx";

            TestExcelWrite(file);

            TestExcelRead(file);

        }

    }

}

View Code

 

1.NPOI下载地址：http://npoi.codeplex.com/releases/view/38113

2.NPOI学习系列教程推荐：http://www.cnblogs.com/tonyqus/archive/2009/04/12/1434209.html

 

参考：

http://www.cnblogs.com/Erik_Xu/archive/2012/06/08/2541957.html

http://www.cnblogs.com/linzheng/archive/2010/12/20/1912137.html

http://www.cnblogs.com/knowledgesea/archive/2012/11/16/2772547.html