NPOI 操作笔记

 public static class ExcelUtil
 {
     // Methods
     public static DataTable GetDataTable(Stream stream)
     {
         HSSFWorkbook workbook;
         try
         {
             workbook = new HSSFWorkbook(stream);
         }
         catch (Exception exception)
         {
             throw exception;
         }
         ISheet sheetAt = workbook.GetSheetAt();
         IEnumerator rowEnumerator = sheetAt.GetRowEnumerator();
         DataTable table = new DataTable();
         IRow row = sheetAt.GetRow();
         if (row != null)
         {
             for (int j = ; j < row.LastCellNum; j++)
             {
                 ICell cell = row.GetCell(j);
                 if (cell == null)
                 {
                     table.Columns.Add("cell" + j.ToString());
                 }
                 else
                 {
                     table.Columns.Add(cell.ToString());
                 }
             }
         }
         int count = table.Columns.Count;
         for (int i = ; rowEnumerator.MoveNext(); i++)
         {
             if (i > )
             {
                 IRow current = (HSSFRow) rowEnumerator.Current;
                 DataRow row3 = table.NewRow();
                 for (int k = ; k < count; k++)
                 {
                     ICell cell2 = current.GetCell(k);
                     if (cell2 == null)
                     {
                         row3[k] = null;
                     }
                     else
                     {
                         row3[k] = cell2.ToString();
                     }
                 }
                 table.Rows.Add(row3);
             }
         }
         return table;
     }

     public static DataTable GetDataTable(string filePath)
     {
         HSSFWorkbook workbook;
         try
         {
             using (FileStream stream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
             {
                 workbook = new HSSFWorkbook(stream);
             }
         }
         catch (Exception exception)
         {
             throw exception;
         }
         ISheet sheetAt = workbook.GetSheetAt();
         IEnumerator rowEnumerator = sheetAt.GetRowEnumerator();
         DataTable table = new DataTable();
         IRow row = sheetAt.GetRow();
         if (row != null)
         {
             for (int j = ; j < row.LastCellNum; j++)
             {
                 ICell cell = row.GetCell(j);
                 if (cell == null)
                 {
                     table.Columns.Add("cell" + j.ToString());
                 }
                 else
                 {
                     table.Columns.Add(cell.ToString());
                 }
             }
         }
         int count = table.Columns.Count;
         for (int i = ; rowEnumerator.MoveNext(); i++)
         {
             if (i > )
             {
                 IRow current = (HSSFRow) rowEnumerator.Current;
                 DataRow row3 = table.NewRow();
                 for (int k = ; k < count; k++)
                 {
                     ICell cell2 = current.GetCell(k);
                     if (cell2 == null)
                     {
                         row3[k] = null;
                     }
                     else
                     {
                         row3[k] = cell2.ToString();
                     }
                 }
                 table.Rows.Add(row3);
             }
         }
         return table;
     }

     /// <summary>
       /// 导入数据到excel文件
       /// </summary>
       /// <param name="data">待导入的数据</param>
       /// <param name="fileName">文件路径</param>
       /// <param name="sheetName">excel表名</param>
       /// <param name="hiddenColmnIndexs">隐藏列索引</param>
       /// <param name="header">列头字典；原始列头=>重命名列名</param>
       /// <param name="redHeaderClomnIndexs">标记红色加粗的列索引</param>
       /// <param name="comments">列头批注字典；列名=>批注内容</param>
       /// <returns></returns>
         public static string SetDataTableToExcel(DataTable data,string fileName, string sheetName, int[] hiddenColmnIndexs = null, Dictionary<string, string> header = null,int[] redHeaderClomnIndexs = null,Dictionary<string,string> comments= null)
         {
             int num4 = ;
             int num = ;
             int column = ;
             int rownum = ;
             ISheet sheet = null;
             IWorkbook workbook = new HSSFWorkbook();
             //todo:tans
            var stream = new FileStream(fileName ,FileMode.OpenOrCreate,FileAccess.ReadWrite);

             try
             {
                 sheet = workbook.CreateSheet(sheetName);

                 IRow row = sheet.CreateRow();
                 column = ;
                 int maxCount = Math.Max(header!=null ? header.Count :  , data.Columns.Count);

                 IDrawing patr1 = sheet.CreateDrawingPatriarch();// as HSSFPatriarch;
                 //创建列头
                 while (column < data.Columns.Count)
                 {
                     var col = data.Columns[column];
                     var colName = col.ColumnName;
                     ICell cell = row.GetCell(column);
                     if (header!=null && header.ContainsKey(colName))
                     {
                         string temp = header[colName];//列重命名
                         header.Remove(colName);
                         cell = row.CreateCell(column);
                         cell.SetCellValue(temp);
                     }
                     //创建批注
                     colName = cell.StringCellValue;
                     if (comments!=null && comments.ContainsKey(colName))
                     {
                         var commentStr = comments[colName];
                         IComment comment1 = patr1.CreateCellComment(new HSSFClientAnchor(, , , , , , , ));// as HSSFComment;
                         comment1.String = new HSSFRichTextString(commentStr);
                         cell.CellComment = comment1;
                     }
                     column++;
                 }
                 //附加列头
                 int colCount = data.Columns.Count;
                 foreach (var colName in header.Keys)
                 {
                     row.CreateCell(colCount).SetCellValue(header[colName]);
                     colCount++;
                 }
                 //设置列头样式
                 redHeaderClomnIndexs = redHeaderClomnIndexs ?? new int[]{};
                 for (int i = , l=, rl= redHeaderClomnIndexs.Length; i < row.Cells.Count; i++,l++)
                 {
                     var cell = row.GetCell(i);
                     if (cell==null)
                     {
                         continue;
                     }
                     //设置字体
                     IFont font = workbook.CreateFont();
                     font.Boldweight = (short)FontBoldWeight.BOLD;
                     if (l < rl)
                     {
                         int index = redHeaderClomnIndexs[l];
                         cell = row.GetCell(index);
                         font.Color = (short)FontColor.RED;
                     }
                     //设置样式
                     ICellStyle style = workbook.CreateCellStyle();
                     style.Alignment = HorizontalAlignment.CENTER;
                     style.SetFont(font);

                     cell.CellStyle = style;
                 }
                //创建数据列，并填充数据
                 rownum = ;
                 for (num = ; num < data.Rows.Count; num++)
                 {
                     IRow row2 = sheet.CreateRow(rownum);
                     for (column = ; column < data.Columns.Count; column++)
                     {
                         row2.CreateCell(column).SetCellValue(data.Rows[num][column].ToString());
                     }
                     rownum++;
                 }
                 //设置隐藏列
                 if (hiddenColmnIndexs != null && hiddenColmnIndexs.Length <= column)
                 {
                     for (int i = , l = hiddenColmnIndexs.Length; i < l; i++)
                     {
                         sheet.SetColumnHidden(hiddenColmnIndexs[i], true);
                     }
                 }
                 //当创建完毕所有cell，设置居中才有效
                 for (int i = ; i < row.Cells.Count; i++)
                 {
                      sheet.AutoSizeColumn(i);
                 }
                 workbook.Write(stream);
             }
             catch (Exception ex)
             {
                 return null;
             }
             finally
             {
                 stream.Close();
             }
            return fileName;
         }
 }