1. The entire Excel table is called a worksheet: WorkBook (workbook), and it contains pages (worksheets): Sheet; Row: Row; Cell.
2. NPOI is the C# version of POI. The index of the row and column of NPOI starts from 0
3. POI reads Excel in two formats, one is HSSF and the other is XSSF. The difference between HSSF and XSSF is as follows:
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.
Namely: HSSF Applicable to versions prior to 2007, XSSF applies to versions 2007 and above.
The following is an example of using NPOI to read and write Excel: The function encapsulated by ExcelHelper is mainly to write data from DataTable to Excel, or to read data from Excel to a DataTable.
ExcelHelper class:
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; //file name
private IWorkbook workbook = null;
private FileStream fs = null;
private bool disposed;
public ExcelHelper(string fileName)
{
this.fileName = fileName;
disposed = false;
}
/// <summary>
/// Import DataTable data into excel
/// </summary>
/// <param name="data">Data to import</param>
/// <param name="isColumnWritten">Does the column name of the DataTable want to be imported</param>
/// <param name="sheetName">The name of the sheet of excel to be imported</param>
/// <returns>Number of rows of imported data (the row containing the column name)</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) //write the column name of the DataTable
{
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); //Write to excel
return count;
}
catch (Exception ex)
{
Console.WriteLine("Exception: " + ex.Message);
return -1;
}
}
/// <summary>
/// Import data from excel into DataTable
/// </summary>
/// <param name="sheetName">excel sheet name</param>
/// <param name="isFirstRowColumn">Whether the first row is the column name of the DataTable</param>
/// <returns>Returned 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) //If the sheet corresponding to the specified sheetName is not found, try to get the first sheet
{
sheet = workbook.GetSheetAt(0);
}
}
else
{
sheet = workbook.GetSheetAt(0);
}
if (sheet != null)
{
IRow firstRow = sheet.GetRow(0);
int cellCount = firstRow.LastCellNum; //The number of the last cell in a row is the total number of columns
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;
}
// last column label
int rowCount = sheet.LastRowNum;
for (int i = startRow; i <= rowCount; ++i)
{
IRow row = sheet.GetRow(i);
if (row == null) continue; //Row with no data defaults to null
DataRow dataRow = data.NewRow();
for (int j = row.FirstCellNum; j < cellCount; ++j)
{
if (row.GetCell(j) != null) //Similarly, cells without data are null by default
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;
}
}
}
}
Test code:
View Code
Check out this article, which is highly read, and update my other version using Aspose.Cells:
PS: Aspose is charged
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 related DLL download: NPOI-Lib.rar
1. NPOI download address: http://npoi.codeplex.com/releases/view/38113
2. Recommended series of NPOI learning tutorials: http://www.cnblogs.com/tonyqus/archive/2009/04/12/1434209.html
refer to:
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