C# Excel使用NPOI

程序处理excel使用using Microsoft.Office.Interop.Excel方式，运行程序需要电脑安装excel，而且excel版本还需要一样，使用起来不方便。使用NPOI不用电脑安装office.

下载地址:http://npoi.codeplex.com/

下载NPOI 2.2.1 binary package.zip，解压缩里面有Net20和Net40。我使用的Net40，把里面所有的dll添加引用。

读excel

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System.IO;
private void ReadPatternExcel(string filePath,int sheetIndex)
{
IWorkbook workBook = null;
ISheet sheet;
try
{
FileInfo fileInfo = new FileInfo(filePath);
if(fileInfo.Exists)
{
FileStream fs = fileInfo.OpenRead();
switch (fileInfo.Extension)
{
//xls是03，用HSSFWorkbook打开，.xlsx是07或者10用XSSFWorkbook打开
case ".xls":
workBook = new HSSFWorkbook(fs);
break;
case ".xlsx":
workBook = new XSSFWorkbook(fs);
break;
default:
break;
}
fs.Close();//关闭文件流
}

if(workBook!=null)
{
sheet = workBook.GetSheetAt(sheetIndex);
IRow headerRow = sheet.GetRow(0);
int colCount = headerRow.LastCellNum;//列数
//遍历
for(int i=sheet.FirstRowNum;i<=sheet.LastRowNum;i++)
{
Console.Write("row "+i.ToString()+" ");
NPOI.SS.UserModel.IRow row = sheet.GetRow(i);//得到一行
for(int j=row.FirstCellNum;j<row.LastCellNum;j++)
{
string data = row.GetCell(j).ToString();
Console.Write(data);
}
Console.WriteLine();
}
}

}
catch(Exception e)
{
MessageBox.Show(e.Message.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
workBook = null;
sheet = null;
}

}

写入Excel

private void ExportToExcel()
{
SaveFileDialog saveFileDlg = new SaveFileDialog();
saveFileDlg.Filter = "Excel|*.xlsx|All file|*.*";
if (saveFileDlg.ShowDialog()==DialogResult.OK)
{
WriteExcel(saveFileDlg.FileName);
}

}

private void WriteExcel(string filePath)
{
IWorkbook workBook = null;
ISheet sheet = null;
FileStream fs=null;
try
{
workBook = new XSSFWorkbook();
sheet = workBook.CreateSheet("sheet0");

//设置列头
IRow row = sheet.CreateRow(0);//excel第一行设为列头
ICell cell = row.CreateCell(0);
cell.SetCellValue("Data");
cell = row.CreateCell(1);
cell.SetCellValue("Remark");

//添加数据
for(int rowIndex=0; rowIndex < collapseDataGridView1.RowCount; rowIndex++)
{
row = sheet.CreateRow(rowIndex+1);
cell = row.CreateCell(0);
cell.SetCellValue(collapseDataGridView1.Rows[rowIndex].Cells[0].Value.ToString());

cell = row.CreateCell(1);
cell.SetCellValue(collapseDataGridView1.Rows[rowIndex].Cells[1].Value.ToString());
}

fs = File.OpenWrite(filePath);
workBook.Write(fs);
MessageBox.Show("导入excel完成！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

}
catch(Exception ex)
{
MessageBox.Show(ex.Message.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);

}
finally
{
workBook = null;
sheet = null;
if(fs!=null)
{
fs.Close();

}

}

}