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：
View Code
签于这篇文章阅读量较高，更新一下我使用Aspose.Cells的另一个版本：
PS：Aspose是要收费的
using System; using System.Collections.Generic; using System.Data; using System.IO; using System.Linq; using System.Text; using Aspose.Cells; namespace NetUtilityLib { public static class ExcelHelper { public static int DataTableToExcel(DataTable data, string fileName, string sheetName, bool isColumnNameWritten) { int num = -1; try { Workbook workBook; Worksheet worksheet = null; if (File.Exists(fileName)) workBook = new Workbook(fileName); else workBook = new Workbook(); if (sheetName == null) { if (workBook.Worksheets.Count > 0) { worksheet = workBook.Worksheets[0]; } else { sheetName = "Sheet1"; workBook.Worksheets.RemoveAt(sheetName); worksheet = workBook.Worksheets.Add(sheetName); } } if (worksheet != null) { worksheet.Cells.Clear(); num = worksheet.Cells.ImportDataTable(data, isColumnNameWritten, 0, 0, false); workBook.Save(fileName); } } catch (Exception ex) { Console.WriteLine(ex.Message); } return num; } public static void AddOneRowToExcel(DataRow dataRow, string fileName, string sheetName) { try { Workbook workBook; if (File.Exists(fileName)) workBook = new Workbook(fileName); else workBook = new Workbook(); Worksheet worksheet=null; if (sheetName == null) { worksheet = workBook.Worksheets[0]; } else { worksheet = workBook.Worksheets[sheetName]; } if (worksheet != null) { worksheet.Cells.ImportDataRow(dataRow, worksheet.Cells.MaxDataRow + 1,0); //worksheet.Cells.ImportArray(dataArray, worksheet.Cells.MaxDataRow+1, 0, false); workBook.Save(fileName); } } catch (Exception ex) { Console.WriteLine(ex.Message); } } public static DataTable ExcelToDataTable(string fileName, string sheetName, bool isFirstRowColumnName) { DataTable data = new DataTable(); try { Workbook workbook = null; FileInfo fileInfo = new FileInfo(fileName); if (fileInfo.Extension.ToLower().Equals(".xlsx")) workbook = new Workbook(fileName, new LoadOptions(LoadFormat.Xlsx)); else if (fileInfo.Extension.ToLower().Equals(".xls")) workbook = new Workbook(fileName, new LoadOptions(LoadFormat.Excel97To2003)); if (workbook != null) { Worksheet worksheet = null; if (sheetName != null) { worksheet = workbook.Worksheets[sheetName]; } else { worksheet = workbook.Worksheets[0]; } if (worksheet != null) { data = worksheet.Cells.ExportDataTable(0, 0, worksheet.Cells.MaxRow+1, worksheet.Cells.MaxColumn+1, isFirstRowColumnName); return data; } } else { return data; } } catch (Exception ex) { Console.WriteLine(ex.Message); } return data; } } }
Excel相关DLL下载：NPOI-Lib.rar
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
本文转自阿凡卢博客园博客，原文链接：http://www.cnblogs.com/luxiaoxun/p/3374992.html，如需转载请自行联系原作者
