---
lang: ja-jp
breaks: true
---
# C# NPOI を使用した、Excelシート内容の読み取り　2021-04-15

## 環境
* Windows Server 2019
* Visual Studio 2017
* .Net Framework 4.5.2
* NPOI 2.3.0.0

## 全てのセルの値を文字列として取得するサンプル

        /// <summary>
        /// 
        /// </summary>
        /// <param name="xlsFile"></param>
        /// <param name="intMaxRowNumber"></param>
        /// <returns></returns>
        private List<string[]> GetXlsData(
            FileInfo xlsFile, 
            int? intMaxRowNumber = null
            )
        {
            List<List<ICell>> lstRows = new List<List<ICell>>();
            using (FileStream stream = xlsFile.OpenRead())
            {
                HSSFWorkbook hssfworkbook = new HSSFWorkbook(stream);
                try
                {
                    ISheet sheet = hssfworkbook.GetSheetAt(0);
                    int intLastRowNumber = sheet.LastRowNum;
                    if (   intMaxRowNumber != null 
                        && intLastRowNumber > intMaxRowNumber
                        )
                    {
                        intLastRowNumber = intMaxRowNumber.Value;
                    }
                    for (int i = 0; i < intLastRowNumber; i++)
                    {
                        IRow row = sheet.GetRow(i);
                        List<ICell> cells = new List<ICell>();
                        if (row != null)
                        {
                            foreach (ICell cell in row)
                            {
                                while (cells.Count < cell.ColumnIndex)
                                {
                                    cells.Add(null as ICell);
                                }
                                cells.Insert(cell.ColumnIndex, cell);
                            }
                        }
                        lstRows.Add(cells);
                    }

                    //IEnumerator rows = sheet.GetRowEnumerator();
                    //while (rows.MoveNext())
                    //{
                    //    IRow row = rows.Current as HSSFRow;
                    //    List<ICell> cells = row.ToList();
                    //    lstRows.Add(cells);
                    //}
                }
                finally
                {
                    hssfworkbook.Close();
                }
            }

            int intMaxCol = lstRows.Max(n => n.Count);
            List<string[]> xlsData = new List<string[]>();
            foreach (List<ICell> row in lstRows)
            {
                string[] strings = new string[intMaxCol];
                int idxCol = 0;
                foreach (ICell cell in row)
                {
                    if (cell != null)
                    {
                        //strings[idxCol] = cell.StringCellValue;
                        strings[idxCol] = cell.ToString();
                    }
                    idxCol++;
                }
                xlsData.Add(strings);
            }

            return xlsData;
        }

###### tags: `NPOI` `C#` `Excel2003`