从数据库中读取数据并写入到Excle电子表格之1

           //获取数据   

          using (SqlDataReader reader = Alian_SQL_Helper.SQL_Helper .ExecuteReader(
                "select CC_AutoId, CC_CustomerName, CC_CellPhone, CC_Landline, CC_Postcode, CC_Email, CC_Address, CC_BranchId, CC_BuyDate, CC_CarNum, CC_BracketNum, CC_Brand, CC_TypeNum, CC_Suggestion, CC_Remarks from T_Customers",
                CommandType.Text))
            {
                if (reader.HasRows)
                {
                    //创建工作薄
                    IWorkbook wk = new HSSFWorkbook ();

                    //创建工作表
                    ISheet sheet = wk.CreateSheet ("24KB" );
                    int num = 0 ;
                    while (reader.Read())
                    {
                        //创建行
                        IRow row = sheet.CreateRow (num);
                        //字段的长度
                        // reader.VisibleFieldCount;
                        //获取当前行中的列数
                        //  reader.FieldCount
                        //获取一个表示指定列中的数据类型的字符串
                        //reader.GetDataTypeName("")
                        for (int i = 0; i < reader.FieldCount; i++)
                        {
                            //创建单元格
                            ICell cell = row.CreateCell (i);
                            if (reader.IsDBNull(i))
                            {
                                cell.SetCellType(CellType .BLANK);
                            }
                            else
                            {
　　　　　　　　　　　　　　　　　　判断数据类型
                                switch (reader.GetDataTypeName(i))
                                {
                                    case "nvarchar" :
                                    case "varchar" :
                                        cell.SetCellType(CellType .STRING);
                                        cell.SetCellValue(reader.GetString(i));
                                        break;
                                    case "int" :
                                        cell.SetCellType(CellType .NUMERIC);
                                        cell.SetCellValue(reader.GetInt32(i));
                                        break;
                                    case "datetime" :

                                        cell.SetCellType(CellType .STRING);
                                        ICellStyle cellStyle = wk.CreateCellStyle();
                                        IDataFormat dataFormat = wk.CreateDataFormat();
                                        cellStyle.DataFormat = dataFormat.GetFormat("yyyy-MM-dd hh:mm:ss" );
                                        cell.CellStyle = cellStyle;
                                        cell.SetCellValue(reader.GetDateTime(i));
                                        break;
                                }
                            }
                        }
                        num++;
                    }
                    using (FileStream fileStreamWrite = File.OpenWrite( "24KK.xls"))
                    {
                        wk.Write(fileStreamWrite );
                    }
                }
            }