using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NPOI.HSSF.UserModel;
using NPOI.SS.Formula.Eval;
using NPOI.SS.Formula.Functions;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using NPOI.POIFS.FileSystem;
using NPOI.HPSF;
using System.IO;
using NPOI.SS.Util;
using System.Drawing;
using NPOI.HSSF.Util;

namespace NPOI
{
    class Program7
    {
        static void Main(string[] args)
        {
            //說明：設定數字格式

            //1.建立EXCEL中的Workbook         
            IWorkbook myworkbook = new XSSFWorkbook();

            //2.建立Workbook中的Sheet        
            ISheet mysheet = myworkbook.CreateSheet("sheet1");
            mysheet.SetColumnWidth(0, 20 * 256);
            mysheet.SetColumnWidth(1, 20 * 256);

            //3.建立Row中的Cell並賦值
            IRow row0 = mysheet.CreateRow(0); row0.CreateCell(0).SetCellValue(2013.143); row0.CreateCell(1).SetCellValue("轉化為漢字大寫");        
            IRow row1 = mysheet.CreateRow(1); row1.CreateCell(0).SetCellValue(123152013.143); row1.CreateCell(1).SetCellValue("改變小數精度");
            IRow row2 = mysheet.CreateRow(2); row2.CreateCell(0).SetCellValue(123152013.143); row2.CreateCell(1).SetCellValue("分段新增，號");
            IRow row3 = mysheet.CreateRow(3); row3.CreateCell(0).SetCellValue(123152013.143); row3.CreateCell(1).SetCellValue("科學計數法");
            IRow row4 = mysheet.CreateRow(4); row4.CreateCell(0).SetCellValue(-123152013.143); row4.CreateCell(1).SetCellValue("正數與負數的區分(負數紅色)");
            IRow row5 = mysheet.CreateRow(5); row5.CreateCell(0).SetCellValue(123152013.77); row5.CreateCell(1).SetCellValue("整數部分+分數");
            IRow row6 = mysheet.CreateRow(6); row6.CreateCell(0).SetCellValue(123152013.77); row6.CreateCell(1).SetCellValue("分數");
            IRow row7 = mysheet.CreateRow(7); row7.CreateCell(0).SetCellValue(0.333); row7.CreateCell(1).SetCellValue("百分數");

            //4.建立CellStyle與DataFormat並載入格式樣式
            IDataFormat dataformat = myworkbook.CreateDataFormat();

            ICellStyle style0 = myworkbook.CreateCellStyle();
            style0.DataFormat = dataformat.GetFormat("[DbNum2][$-804]General");//轉化為漢字大寫

            ICellStyle style1 = myworkbook.CreateCellStyle();
            style1.DataFormat = dataformat.GetFormat("0.0"); //改變小數精度【小數點後有幾個0表示精確到小數點後幾位】

            ICellStyle style2 = myworkbook.CreateCellStyle();
            style2.DataFormat = dataformat.GetFormat("#,##0.0");//分段新增，號

            ICellStyle style3 = myworkbook.CreateCellStyle();
            style3.DataFormat = dataformat.GetFormat("0.00E+00");//科學計數法

            ICellStyle style4 = myworkbook.CreateCellStyle();
            style4.DataFormat = dataformat.GetFormat("0.00;[Red]-0.00");//正數與負數的區分

            ICellStyle style5 = myworkbook.CreateCellStyle();
            style5.DataFormat = dataformat.GetFormat("# ??/??");//整數部分+分數

            ICellStyle style6 = myworkbook.CreateCellStyle();
            style6.DataFormat = dataformat.GetFormat("??/??");//分數

            ICellStyle style7 = myworkbook.CreateCellStyle();
            style7.DataFormat = dataformat.GetFormat("0.00%");//百分數【小數點後有幾個0表示精確到顯示小數點後幾位】

            //5.將CellStyle應用於具體單元格
            row0.GetCell(0).CellStyle = style0;
            row1.GetCell(0).CellStyle = style1;
            row2.GetCell(0).CellStyle = style2;
            row3.GetCell(0).CellStyle = style3;
            row4.GetCell(0).CellStyle = style4;
            row5.GetCell(0).CellStyle = style5;
            row6.GetCell(0).CellStyle = style6;
            row7.GetCell(0).CellStyle = style7;
         
            //6.儲存       
            FileStream file = new FileStream(@"E:\myworkbook7.xlsx", FileMode.Create);
            myworkbook.Write(file);
            file.Close();
        }
    }
}
 

執行後，效果如下圖所示【演示了不同數字格式的設定】