C# 使用NPOI做excel导出

使用NPOI做excel文件导出 :

1.下载npoi引用文件

   下载地址1：https://archive.codeplex.com/?p=npoi

   下载地址2：链接：https://pan.baidu.com/s/1Zxq4NOCnaekdTei74d6UiQ 
                       提取码：zrwn 

   下载地址3：https://download.csdn.net/download/lmqzhzy/11175088

2.代码 

public class ExcelToFile
    {

        /// 

        /// 获取单元格类型
        /// 
        /// 
        /// 
        private static object GetValueType(ICell cell)
        {
            if (cell == null)
                return null;
            switch (cell.CellType)
            {
                case CellType.Blank: //BLANK:  
                    return null;
                case CellType.Boolean: //BOOLEAN:  
                    return cell.BooleanCellValue;
                case CellType.Numeric: //NUMERIC:  
                    return cell.NumericCellValue;
                case CellType.String: //STRING:  
                    return cell.StringCellValue;
                case CellType.Error: //ERROR:  
                    return cell.ErrorCellValue;
                case CellType.Formula: //FORMULA:  
                default:
                    return "=" + cell.CellFormula;
            }
        }

        public static string getFilePath()
        {
            string desktop = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            Console.WriteLine(desktop);//桌面路径
           // Console.ReadLine();

            string fileName = DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".xls"; // 文件名称
            string urlPath = desktop + "/" + fileName; // 文件下载的URL地址
            Console.WriteLine(urlPath);
            return urlPath;
        }
      
        public  static string  exportExcel(T_Operation[] otn)
        {
            IWorkbook workbook;
            string file = getFilePath();
            string fileExt = Path.GetExtension(file).ToLower();
            if (string.IsNullOrEmpty(fileExt) == false)
            {
                if (fileExt == ".xlsx")
                {
                    workbook = new XSSFWorkbook();
                }
                else if (fileExt == ".xls")
                {
                    workbook = new HSSFWorkbook();
                }
                else
                {
                    workbook = null;
                }
                if (workbook == null)
                {
                    return "没有工作簿";
                }
            }
            else
            {
                return "导出路径出错";
            }

            //ISheet sheet = string.IsNullOrEmpty(dt.TableName) ? workbook.CreateSheet("Sheet1") : workbook.CreateSheet(dt.TableName);
            ISheet sheet = workbook.CreateSheet("sheet1");

            //表头  
            IRow row = sheet.CreateRow(0);
            row.CreateCell(0).SetCellValue("ID");
            row.CreateCell(1).SetCellValue("名称");
            row.CreateCell(2).SetCellValue("名称");
            row.CreateCell(3).SetCellValue("名称");
            row.CreateCell(4).SetCellValue("名称");
            row.CreateCell(5).SetCellValue("名称");
            row.CreateCell(6).SetCellValue("名称");
            row.CreateCell(7).SetCellValue("名称");
            row.CreateCell(8).SetCellValue("名称");

            //数据  
            for (int i = 0, count = otn.Count(); i < count; i++)
            {
                IRow row1 = sheet.CreateRow(i + 1);
                for(int j = 0; j < 9; j++)
                {
                    ICell cell = row1.CreateCell(j);
                }
                
                T_Operation operation = otn[i];
                row1.GetCell(0).SetCellValue(operation.ID);
                row1.GetCell(1).SetCellValue(operation.字段1.ToString());
                row1.GetCell(2).SetCellValue(operation.字段2.ToString());
                row1.GetCell(3).SetCellValue(operation.字段3.ToString());
                row1.GetCell(4).SetCellValue(operation.字段4.ToString());
                row1.GetCell(5).SetCellValue(operation.字段5.ToString());
                row1.GetCell(6).SetCellValue(operation.字段6.ToString());

                row1.GetCell(7).SetCellValue(operation.字段7.ToString());
                row1.GetCell(8).SetCellValue(operation.字段8.ToString());

            }

            //转为字节数组  
            MemoryStream stream = new MemoryStream();
            workbook.Write(stream); 
            var buf = stream.ToArray();

            //保存为Excel文件  
            using (FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write))
            {
                fs.Write(buf, 0, buf.Length);
                fs.Flush();
            }
            return "ok";
        }
    }