注意，Excel读入DataTable需要使用NPOI包

/// <summary>/// Excel导入成Datable/// </summary>/// <param name="file">导入路径(包含文件名与扩展名)</param>/// <returns></returns>public static DataTable ExcelToTable(string file, string sheetName = ""){DataTable dt = new DataTable();IWorkbook workbook = null;try{string fileExt = Path.GetExtension(file).ToLower();using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read)){//XSSFWorkbook 适用XLSX格式，HSSFWorkbook 适用XLS格式if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(fs); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(fs); } else { workbook = null; }if (workbook == null) { return null; }ISheet sheet = string.IsNullOrWhiteSpace(sheetName) ? workbook.GetSheetAt(0) : workbook.GetSheet(sheetName);//表头  IRow header = sheet.GetRow(sheet.FirstRowNum);if (header == null){throw new Exception("Excel表没有数据，请添加数据");}List<int> columns = new List<int>();for (int i = 0; i < header.LastCellNum; i++){object obj = GetValueType(header.GetCell(i));if (obj == null || obj.ToString().Trim() == string.Empty){continue;}else{dt.Columns.Add(new DataColumn(obj.ToString()));}columns.Add(i);}//数据  for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++){DataRow dr = dt.NewRow();bool hasValue = false;foreach (int j in columns){if (sheet.GetRow(i) != null) {dr[j] = GetValueType(sheet.GetRow(i).GetCell(j));}//if (dr[j] != null && dr[j].ToString() != string.Empty)//{//  hasValue = true;//}}//if (hasValue)//{//  dt.Rows.Add(dr);//}dt.Rows.Add(dr);}dt.AcceptChanges();}return dt;}catch (Exception e){return null;}finally{if (dt != null) { dt.Dispose(); }if (workbook != null) { workbook = null; }}}/// <summary>/// 获取单元格类型/// </summary>/// <param name="cell"></param>/// <returns></returns>private static object GetValueType(ICell cell){if (cell == null)return null;switch (cell.CellType){case CellType.Blank: //BLANK:  return "";case CellType.Boolean: //BOOLEAN:  return cell.BooleanCellValue;case CellType.Numeric: //NUMERIC:  return cell.NumericCellValue;case CellType.String: //STRING:  return cell.StringCellValue;case CellType.Error: //ERROR:  return cell.ErrorCellValue;case CellType.Formula: //FORMULA:  default:return "=" + cell.CellFormula;}}

DataTable读入Excel

/// <summary>/// Datatable生成Excel表格并返回路径/// </summary>/// <param name="m_DataTable">Datatable</param>/// <param name="s_FileName">文件名</param>/// <returns></returns>public static string DataToExcel(System.Data.DataTable m_DataTable, string s_FileName){//string FileName = @"C:\Users\JK\Desktop\DataTableToExcel\" + s_FileName + ".xlsx";  //文件存放路径string FileName = s_FileName;if (System.IO.File.Exists(FileName))                                //存在则删除{System.IO.File.Delete(FileName);}System.IO.FileStream objFileStream;System.IO.StreamWriter objStreamWriter;string strLine = "";objFileStream = new System.IO.FileStream(FileName, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Write);objStreamWriter = new System.IO.StreamWriter(objFileStream, Encoding.Unicode);for (int i = 0; i < m_DataTable.Columns.Count; i++){strLine = strLine + m_DataTable.Columns[i].Caption.ToString() + Convert.ToChar(9);      //写列标题}objStreamWriter.WriteLine(strLine);strLine = "";for (int i = 0; i < m_DataTable.Rows.Count; i++){for (int j = 0; j < m_DataTable.Columns.Count; j++){if (m_DataTable.Rows[i].ItemArray[j] == null)strLine = strLine + " " + Convert.ToChar(9);                                    //写内容else{string rowstr = "";rowstr = m_DataTable.Rows[i].ItemArray[j].ToString();if (rowstr.IndexOf("\r\n") > 0)rowstr = rowstr.Replace("\r\n", " ");if (rowstr.IndexOf("\t") > 0)rowstr = rowstr.Replace("\t", " ");strLine = strLine + rowstr + Convert.ToChar(9);}}objStreamWriter.WriteLine(strLine);strLine = "";}objStreamWriter.Close();objFileStream.Close();return FileName;        //返回生成文件的绝对路径}