创建应用程序

这里直接创建Console程序

引用NPOI的NuGet包

• PM> Install-Package NPOI -Version 2.5.1

• 直接Nuget包管理器添加

导入Excel

  public static string ReadExcel()
        {
            DataTable dtTable = new DataTable();
            List<string> rowList = new List<string>();
            ISheet sheet;
            try
            {
                using (var stream = new FileStream(InputPath, FileMode.Open))
                {
                    stream.Position = 0;
                    XSSFWorkbook xssWorkbook = new XSSFWorkbook(stream);
                    sheet = xssWorkbook.GetSheetAt(0);
                    IRow headerRow = sheet.GetRow(0);
                    int cellCount = headerRow.LastCellNum;
                    for (int j = 0; j < cellCount; j++)
                    {
                        ICell cell = headerRow.GetCell(j);
                        if (cell == null || string.IsNullOrWhiteSpace(cell.ToString())) continue;
                        {
                            dtTable.Columns.Add(cell.ToString());
                        }
                    }
                    for (int i = (sheet.FirstRowNum + 1); i <= sheet.LastRowNum; i++)
                    {
                        IRow row = sheet.GetRow(i);
                        if (row == null) continue;
                        if (row.Cells.All(d => d.CellType == CellType.Blank)) continue;
                        for (int j = row.FirstCellNum; j < cellCount; j++)
                        {
                            if (row.GetCell(j) != null)
                            {
                                if (!string.IsNullOrEmpty(row.GetCell(j).ToString()) && !string.IsNullOrWhiteSpace(row.GetCell(j).ToString()))
                                {
                                    rowList.Add(row.GetCell(j).ToString());
                                }
                            }
                        }
                        if (rowList.Count > 0)
                            dtTable.Rows.Add(rowList.ToArray());
                        rowList.Clear();
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"ReadExcel: {ex.Message}");
            }

            return JsonConvert.SerializeObject(dtTable);
        }

转为数据实体

• 创建实体类

  public class ConvertDataModel
  {
  public string EID { get; set; }
  public string SECURITY_CODE { get; set; }
  public string SECURITY_INNER_CODE { get; set; }

      public string CHANGE_DATE { get; set; }
  public string NAME_ABBR_CH { get; set; }
  }

• 转换

  var sorc = JsonConvert.DeserializeObject>(str);

导出Excel

 public static void WriteExcel(List<ConvertDataModel> convertDatas)
        {
            // Lets converts our object data to Datatable for a simplified logic.
            // Datatable is most easy way to deal with complex datatypes for easy reading and formatting.
            try
            {
                DataTable table = (DataTable)JsonConvert.DeserializeObject(JsonConvert.SerializeObject(convertDatas), (typeof(DataTable)));
                var memoryStream = new MemoryStream();

                using (var fs = new FileStream(OutputPath, FileMode.Create, FileAccess.Write))
                {
                    IWorkbook workbook = new XSSFWorkbook();
                    ISheet excelSheet = workbook.CreateSheet("Sheet1");

                    List<String> columns = new List<string>();
                    IRow row = excelSheet.CreateRow(0);
                    int columnIndex = 0;

                    foreach (DataColumn column in table.Columns)
                    {
                        columns.Add(column.ColumnName);
                        row.CreateCell(columnIndex).SetCellValue(column.ColumnName);
                        columnIndex++;
                    }

                    int rowIndex = 1;
                    foreach (DataRow dsrow in table.Rows)
                    {
                        row = excelSheet.CreateRow(rowIndex);
                        int cellIndex = 0;
                        foreach (String col in columns)
                        {
                            row.CreateCell(cellIndex).SetCellValue(dsrow[col].ToString());
                            cellIndex++;
                        }

                        rowIndex++;
                    }
                    workbook.Write(fs);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"WriteExcel: {ex.Message}");
            }
        }

引用： https://www.thecodebuzz.com/read-and-write-excel-file-in-net-core-using-npoi/