NPOI导出excel（2.0.6版本）

public static void WriteExcel(System.Data.DataTable dt,string fileName)
        {

            NPOI.XSSF.UserModel.XSSFWorkbook book = new NPOI.XSSF.UserModel.XSSFWorkbook();
            NPOI.SS.UserModel.ISheet sheet = book.CreateSheet(dt.TableName);

            NPOI.SS.UserModel.IRow row = sheet.CreateRow(0);

            row.HeightInPoints = 25;

            NPOI.SS.UserModel.ICellStyle headStyle = book.CreateCellStyle();
            headStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
            headStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
            headStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
            headStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;
            headStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;
            headStyle.VerticalAlignment = NPOI.SS.UserModel.VerticalAlignment.Justify;
            headStyle.FillForegroundColor = NPOI.HSSF.Util.HSSFColor.PaleBlue.Index;
            headStyle.FillPattern = NPOI.SS.UserModel.FillPattern.SolidForeground;
            NPOI.SS.UserModel.IFont font = book.CreateFont();
            font.Boldweight = (short)NPOI.SS.UserModel.FontBoldWeight.Bold;
            headStyle.SetFont(font);

            NPOI.SS.UserModel.ICellStyle style = book.CreateCellStyle();
            style.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
            style.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
            style.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
            style.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;
            style.VerticalAlignment = NPOI.SS.UserModel.VerticalAlignment.Justify;

            for (int i = 0; i < dt.Columns.Count; i++)
            {
                NPOI.SS.UserModel.ICell cell = row.CreateCell(i);

                cell.CellStyle = headStyle;
                cell.SetCellValue(dt.Columns[i].ColumnName);
            }

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                NPOI.SS.UserModel.IRow row2 = sheet.CreateRow(i + 1);

                row2.HeightInPoints = 20;

                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    NPOI.SS.UserModel.ICell cell = row2.CreateCell(j);
                    
                    cell.CellStyle = style;
                    cell.SetCellValue(Convert.ToString(dt.Rows[i][j]));
                }
            }

            //自适应列宽度
            for (int i = 0; i <= dt.Columns.Count; i++)
            {
                sheet.AutoSizeColumn(i);
            }

            FileStream fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            book.Write(fs);
            fs.Dispose();
            book = null;           
        }

niop2.0.6