如何使用 NPOI c# 将 xls 文件保存为 xlsx 文件？

Question

我正在使用 NPOI 打开 XLS 文件，然后对 XLS 文件添加一些修改。最后我想将它保存为 XLSX 文件。

我正在使用此代码将其保存为 XLS 文件：

using (var fs = new FileStream(Name, FileMode.Create, FileAccess.Write))
{
     wb.Write(fs);
}

是否可以使用 C# 中的 NPOI 将此 XLS 文件另存为 XLSX 文件 ？

提前感谢您的回复

Answer 1

一般来说是可以的，但不是很容易，而是相当复杂的任务。

XLS 文件格式由 HSSFWorkbook class 处理（并根据 HSSFSheet 依此类推）。
XLSX 文件格式由 XSSFWorkbook class（以及 XSSFSheet 等）处理。

因此，为了在使用 NPOI 打开和修改文件后将其保存为 XLSX，您需要创建新的 XSSFWorkbook，然后对于源文件的每个工作表，您需要创建适当的 XSSFSheet，将数据从原始工作表复制到其中，依此类推，直到获得数据的完整副本，然后将工作簿保存到文件。

Answer 2

这是一个老问题，但我遇到过类似的问题。此代码使用 https://npoi.codeplex.com/releases. This code is based on code from 问题中的 NPOI 2.2.1，但它转换 xls->xlsx，而不是 xlsx->xls。此外，它还可以转换样式并修复范围错误。此代码适用于没有图表和其他复杂内容的简单工作簿。

using NPOI.XSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.SS.Util;
using NPOI.HSSF.UserModel;
using System.Collections.Generic;
using System.Linq;
using System.IO;

namespace XlsToXlsxConverter
{
    public static class XLSToXLSXConverter
    {
        public static byte[] Convert(Stream sourceStream)
        {
            var source = new HSSFWorkbook(sourceStream);
            var destination = new XSSFWorkbook();
            for (int i = 0; i < source.NumberOfSheets; i++)
            {
                var xssfSheet = (XSSFSheet)destination.CreateSheet(source.GetSheetAt(i).SheetName);
                var hssfSheet = (HSSFSheet)source.GetSheetAt(i);
                CopyStyles(hssfSheet, xssfSheet);
                CopySheets(hssfSheet, xssfSheet);
            }
            using (var ms = new MemoryStream())
            {
                destination.Write(ms);
                return ms.ToArray();
            }
        }

        private static void CopyStyles(HSSFSheet from, XSSFSheet to)
        {
            for (short i = 0; i <= from.Workbook.NumberOfFonts; i++)
            {
                CopyFont(to.Workbook.CreateFont(), from.Workbook.GetFontAt(i));
            }

            for (short i = 0; i < from.Workbook.NumCellStyles; i++)
            {
                CopyStyle(to.Workbook.CreateCellStyle(), from.Workbook.GetCellStyleAt(i), to.Workbook, from.Workbook);
            }

        }

        private static void CopyFont(IFont toFront, IFont fontFrom)
        {
            toFront.Boldweight = fontFrom.Boldweight;
            toFront.Charset = fontFrom.Charset;
            toFront.Color = fontFrom.Color;
            toFront.FontHeightInPoints = fontFrom.FontHeightInPoints;            
            toFront.FontName = fontFrom.FontName;           
            toFront.IsBold = fontFrom.IsBold;
            toFront.IsItalic = fontFrom.IsItalic;
            toFront.IsStrikeout = fontFrom.IsStrikeout;
            //toFront.Underline = fontFrom.Underline; <- bug in npoi setter
        }

        private static void CopyStyle(ICellStyle toCellStyle, ICellStyle fromCellStyle, IWorkbook toWorkbook, IWorkbook fromWorkbook)
        {
            toCellStyle.Alignment = fromCellStyle.Alignment;
            toCellStyle.BorderBottom = fromCellStyle.BorderBottom;
            toCellStyle.BorderDiagonal = fromCellStyle.BorderDiagonal;
            toCellStyle.BorderDiagonalColor = fromCellStyle.BorderDiagonalColor;
            toCellStyle.BorderDiagonalLineStyle = fromCellStyle.BorderDiagonalLineStyle;
            toCellStyle.BorderLeft = fromCellStyle.BorderLeft;
            toCellStyle.BorderRight = fromCellStyle.BorderRight;
            toCellStyle.BorderTop = fromCellStyle.BorderTop;
            toCellStyle.BottomBorderColor = fromCellStyle.BottomBorderColor;
            toCellStyle.DataFormat = fromCellStyle.DataFormat;
            toCellStyle.FillBackgroundColor = fromCellStyle.FillBackgroundColor;
            toCellStyle.FillForegroundColor = fromCellStyle.FillForegroundColor;
            toCellStyle.FillPattern = fromCellStyle.FillPattern;
            toCellStyle.Indention = fromCellStyle.Indention;
            toCellStyle.IsHidden = fromCellStyle.IsHidden;
            toCellStyle.IsLocked = fromCellStyle.IsLocked;
            toCellStyle.LeftBorderColor = fromCellStyle.LeftBorderColor;
            toCellStyle.RightBorderColor = fromCellStyle.RightBorderColor;
            toCellStyle.Rotation = fromCellStyle.Rotation;
            toCellStyle.ShrinkToFit = fromCellStyle.ShrinkToFit;
            toCellStyle.TopBorderColor = fromCellStyle.TopBorderColor;
            toCellStyle.VerticalAlignment = fromCellStyle.VerticalAlignment;
            toCellStyle.WrapText = fromCellStyle.WrapText;

            toCellStyle.SetFont(toWorkbook.GetFontAt((short)(fromCellStyle.GetFont(fromWorkbook).Index + 1 )));
        }

        private static void CopySheets(HSSFSheet source, XSSFSheet destination)
        {
            var maxColumnNum = 0;
            var mergedRegions = new List<CellRangeAddress>();
            var styleMap = new Dictionary<int, HSSFCellStyle>();
            for (int i = source.FirstRowNum; i <= source.LastRowNum; i++)
            {
                var srcRow = (HSSFRow)source.GetRow(i);
                var destRow = (XSSFRow)destination.CreateRow(i);
                if (srcRow != null)
                {
                    CopyRow(source, destination, srcRow, destRow, mergedRegions);
                    if (srcRow.LastCellNum > maxColumnNum)
                    {
                        maxColumnNum = srcRow.LastCellNum;
                    }
                }
            }
            for (int i = 0; i <= maxColumnNum; i++)
            {
                destination.SetColumnWidth(i, source.GetColumnWidth(i));
            }
        }

        private static void CopyRow(HSSFSheet srcSheet, XSSFSheet destSheet, HSSFRow srcRow, XSSFRow destRow, List<CellRangeAddress> mergedRegions)
        {
            destRow.Height = srcRow.Height;

            for (int j = srcRow.FirstCellNum; srcRow.LastCellNum >= 0 && j <= srcRow.LastCellNum; j++)
            {
                var oldCell = (HSSFCell)srcRow.GetCell(j);
                var newCell = (XSSFCell)destRow.GetCell(j);
                if (oldCell != null)
                {
                    if (newCell == null)
                    {
                        newCell = (XSSFCell)destRow.CreateCell(j);
                    }

                    CopyCell(oldCell, newCell);

                    var mergedRegion = GetMergedRegion(srcSheet, srcRow.RowNum,
                            (short)oldCell.ColumnIndex);

                    if (mergedRegion != null)
                    {
                        var newMergedRegion = new CellRangeAddress(mergedRegion.FirstRow,
                                mergedRegion.LastRow, mergedRegion.FirstColumn, mergedRegion.LastColumn);
                        if (IsNewMergedRegion(newMergedRegion, mergedRegions))
                        {
                            mergedRegions.Add(newMergedRegion);
                            destSheet.AddMergedRegion(newMergedRegion);
                        }
                    }
                }
            }
        }

        private static void CopyCell(HSSFCell oldCell, XSSFCell newCell)
        {
            CopyCellStyle(oldCell, newCell);

            CopyCellValue(oldCell, newCell);
        }

        private static void CopyCellValue(HSSFCell oldCell, XSSFCell newCell)
        {
            switch (oldCell.CellType)
            {
                case CellType.String:
                    newCell.SetCellValue(oldCell.StringCellValue);
                    break;
                case CellType.Numeric:
                    newCell.SetCellValue(oldCell.NumericCellValue);
                    break;
                case CellType.Blank:
                    newCell.SetCellType(CellType.Blank);
                    break;
                case CellType.Boolean:
                    newCell.SetCellValue(oldCell.BooleanCellValue);
                    break;
                case CellType.Error:
                    newCell.SetCellErrorValue(oldCell.ErrorCellValue);
                    break;
                case CellType.Formula:
                    newCell.SetCellFormula(oldCell.CellFormula);
                    break;
                default:
                    break;
            }
        }

        private static void CopyCellStyle(HSSFCell oldCell, XSSFCell newCell)
        {
            if (oldCell.CellStyle == null) return;
            newCell.CellStyle = newCell.Sheet.Workbook.GetCellStyleAt((short)(oldCell.CellStyle.Index + 1));


        }

        private static CellRangeAddress GetMergedRegion(HSSFSheet sheet, int rowNum, short cellNum)
        {
            for (var i = 0; i < sheet.NumMergedRegions; i++)
            {
                var merged = sheet.GetMergedRegion(i);
                if (merged.IsInRange(rowNum, cellNum))
                {
                    return merged;
                }
            }
            return null;
        }

        private static bool IsNewMergedRegion(CellRangeAddress newMergedRegion,
                List<CellRangeAddress> mergedRegions)
        {
            return !mergedRegions.Any(r =>
            r.FirstColumn == newMergedRegion.FirstColumn &&
            r.LastColumn == newMergedRegion.LastColumn &&
            r.FirstRow == newMergedRegion.FirstRow &&
            r.LastRow == newMergedRegion.LastRow);
        }
    }
}

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