NPOI读取Excel文件

 public class ExcelOperator
     {
         public static List<DataTable> Read(string fileName)
         {
             List<DataTable> tables = new List<DataTable>();
             if (!File.Exists(fileName))
                 return tables;
             var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
             IWorkbook workbook = null;
             if (fileName.IndexOf(".xlsx") > )
             {
                 // 2007版本
                 workbook = new XSSFWorkbook(fs);
             }
             else if (fileName.IndexOf(".xls") > )
             {
                 // 2003版本
                 workbook = new HSSFWorkbook(fs);
             }

             var workbooks = workbook.GetEnumerator();
             while (workbooks.MoveNext())
             {
                 ISheet sheet = workbooks.Current as ISheet;
                 DataTable dt = new DataTable(sheet.SheetName);
                 var rows = sheet.GetRowEnumerator();
                 while (rows.MoveNext())
                 {
                     IRow row = rows.Current as IRow;
                     if (row.RowNum == )
                     {
                         row.Cells.ForEach(cell =>
                         {
                             dt.Columns.Add(cell.StringCellValue);
                         });
                     }
                     else
                     {
                         var dr = dt.NewRow();
                         for (int i = ; i < row.Cells.Count; i++)
                         {
                             dr[i] = row.Cells[i].ToString();
                         }
                         dt.Rows.Add(dr);
                     }
                 }

                 tables.Add(dt);
             }
             return tables;
         }
     }

读取整个EXCEL方法

 public static DataTable ReadExcel(string fileName, string sheetname)
         {
             if (!File.Exists(fileName))
                 return null;
             var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
             IWorkbook workbook = null;
             if (fileName.IndexOf(".xlsx") > )
             {
                 // 2007版本
                 workbook = new XSSFWorkbook(fs);
             }
             else if (fileName.IndexOf(".xls") > )
             {
                 // 2003版本
                 workbook = new HSSFWorkbook(fs);
             }
             ISheet sheet = workbook.GetSheet(sheetname);
             DataTable dt = new DataTable();
             var rows = sheet.GetRowEnumerator();
             while (rows.MoveNext())
             {
                 IRow row = rows.Current as IRow;
                 if (row.RowNum == )
                 {
                     row.Cells.ForEach(cell =>
                     {
                         dt.Columns.Add(cell.StringCellValue);
                     });
                 }
                 else
                 {
                     var dr = dt.NewRow();
                     for (int i = ; i < row.Cells.Count; i++)
                     {
                         dr[i] = row.Cells[i].ToString();
                     }
                     dt.Rows.Add(dr);
                 }
             }
             return dt;
         }

读取指定SheetName的表