NPOI操作EXCEL的简单例子

 1.将DataTable生成XLS文件

  用一个单独类来写的哦。

        public static void Import(DataTable dt, string filename)
        {
            //创建空白文档
            HSSFWorkbook workbook = new HSSFWorkbook();
            //创建标准三页
            HSSFSheet sheet1 = workbook.CreateSheet("sheet1");
            HSSFSheet sheet2 = workbook.CreateSheet("sheet2");
            HSSFSheet sheet3 = workbook.CreateSheet("sheet3");
            HSSFRow headrow = sheet1.CreateRow(0);//创建第一行
            //将DataTable的列写入第一行
            foreach (DataColumn column in dt.Columns)
            {
                //column.Oradinal,列的位置,column.ColumnName,列名
                headrow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);//写入
              
            }

            //再写入记录值 
            HSSFRow row;
            for (int i = 0; i < dt.Rows.Count;i++ )
            {
                row = sheet1.CreateRow(i + 1);
                for (int j = 0; j < dt.Columns.Count;j++ )
                {
                    row.CreateCell(j).SetCellValue(dt.Rows[i][j].ToString());//dataTable和EXCEL差不多都是一个二维数组一样的.
                }

            }

            using(FileStream file=new FileStream(@"d:\"+filename+"",FileMode.Create))
            {
                workbook.Write(file);//写入
                file.Dispose();
                
            }
        
        }

 

   调用的时候，简单的

 DataTable dt=SqlHelper.ExecuteAdapter("select id as '编号',name as '姓名',bus as '交通工具',tel as '电话号码' from Employee");
           NPOIDataTable.Import(dt,"16.xls");

 

2.EXCEL写入DataTable中

  public static DataTable ImportData(string filename)
        {
            DataTable dt=new DataTable();
            HSSFWorkbook workbook;
            using(FileStream file=new FileStream(filename,FileMode.Open,FileAccess.Read))
            {
              workbook=new HSSFWorkbook(file);//读入Steam流
            }

            HSSFSheet sheet = workbook.GetSheetAt(0);//获取第一页
            HSSFRow headrow = sheet.GetRow(0);//得到第一行
            HSSFCell cell;
            for (int i = 0; i < headrow.LastCellNum; i++)
            {
                cell = headrow.GetCell(i);
                dt.Columns.Add(cell.ToString());
            
            }

            for (int i = 0; i < sheet.LastRowNum; i++)
            {
                HSSFRow row = sheet.GetRow(i + 1);
                DataRow datarow = dt.NewRow();//新建一行
                for (int j = row.FirstCellNum; j < row.LastCellNum;j++ )
                {
                    datarow[j] = row.GetCell(j).ToString();//一行中，各个列的值
                }
                dt.Rows.Add(datarow);
            }


                return dt;

        }