NPOI开源组件（操作Execl）创建Workbook和Sheet,创建单元格,设置行列样式等

using NPOI.SS.UserModel;
using NPOI.HSSF.UserModel;

//创建Execl
IWorkbook hssfworkbook =new HSSFWorkbook();

//创建一个Sheet
hssfworkbook.CreateSheet("Sheet1");

//HSSFWorkbook实例写入文件
FileStream file = new FileStream(@"test.xls", FileMode.Create);
hssfworkbook.Write(file);
file.Close();

//要创建单元格首先要创建单元格所在的行，比如，下面的代码创建了第0行：
ISheet sheet1 = hssfworkbook.CreateSheet("Sheet1");
IRow row1=sheet1.CreateRow(0);

//行建好了，就可以建单元格了，比如创建A1位置的单元格：
row1.CreateCell(0).SetCellValue("This is a Sample");

//或者sheet1.GetRow(0).CreateCell(0).SetCellValue("This is a Sample");

//set header text 设置页眉
s1.Header.Center = "This is a test sheet";
//set footer text 设置页脚
s1.Footer.Left = "Copyright NPOI Team";
s1.Footer.Right = "created by 123";

//set date format 设置单元格格式
ICellStyle cellStyle = hssfworkbook.CreateCellStyle();
IDataFormat format = hssfworkbook.CreateDataFormat();
cellStyle.DataFormat = format.GetFormat("yyyy年m月d日");
//cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("0.00"); 单元格格式为“0.00”来表示,"￥#,##0"美元显示,"0.00%"百分比显示
cell.CellStyle=cellStyle;

//合并单元格
IRow row = sheet.CreateRow(0);
ICell cell = row.CreateCell(0);
cell.SetCellValue("Sales Report");
ICellStyle style = hssfworkbook.CreateCellStyle();
style.Alignment = HorizontalAlignment.CENTER;
IFont font = hssfworkbook.CreateFont();
font.FontHeight = 20*20;
style.SetFont(font);
cell.CellStyle = style;
sheet.AddMergedRegion(new Region(0, 0, 0, 5));