public DataTable GetExcelTableByOleDB(string strExcelPath, string tableName)
 {
   try
   {
     DataTable dtExcel = new DataTable();
     //数据表
     DataSet ds = new DataSet();
     //获取文件扩展名
     string strExtension = System.IO.Path.GetExtension(strExcelPath);
     string strFileName = System.IO.Path.GetFileName(strExcelPath);
     //Excel的连接
     OleDbConnection objConn = null;
     switch (strExtension)
     {
       case ".xls":
         objConn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + strExcelPath + ";" + "Extended Properties=\"Excel 8.0;HDR=NO;IMEX=1;\"");
         break;
       case ".xlsx":
         objConn = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + strExcelPath + ";" + "Extended Properties=\"Excel 12.0;HDR=NO;IMEX=1;\"");
         break;
       default:
         objConn = null;
         break;
     }
     if (objConn == null)
     {
       return null;
     }
     objConn.Open();
     //获取Excel中所有Sheet表的信息
     //System.Data.DataTable schemaTable = objConn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, null);
     //获取Excel的第一个Sheet表名
     //string tableName = schemaTable.Rows[0][2].ToString().Trim();
     string strSql = "select * from [" + tableName + "]";
     //获取Excel指定Sheet表中的信息
     OleDbCommand objCmd = new OleDbCommand(strSql, objConn);
     OleDbDataAdapter myData = new OleDbDataAdapter(strSql, objConn);
     myData.Fill(ds, tableName);//填充数据
     objConn.Close();
     //dtExcel即为excel文件中指定表中存储的信息
     dtExcel = ds.Tables[tableName];
     return dtExcel;
   }
   catch
   {
     return null;
   }
 }

 //objConn为读取Excel的链接，下面通过过滤来获取有效的Sheet页名称集合
  System.Data.DataTable schemaTable = objConn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, null);
  List<string> lstSheetNames = new List<string>();
  for (int i = 0; i < schemaTable.Rows.Count; i++)
  {
    string strSheetName = (string)dtSheetName.Rows[i]["TABLE_NAME"];
    if (strSheetName.Contains("$") && !strSheetName.Replace("'", "").EndsWith("$"))
    {
      //过滤无效SheetName完毕....
      continue;
    }
    if (lstSheetNames != null && !lstSheetNames.Contains(strSheetName))
      lstSheetNames.Add(strSheetName);
  }

 private Stopwatch wath = new Stopwatch();
 /// <summary>
 /// 使用COM读取Excel
 /// </summary>
 /// <param name="excelFilePath">路径</param>
 /// <returns>DataTabel</returns>
 public System.Data.DataTable GetExcelData(string excelFilePath)
 {
   Excel.Application app = new Excel.Application();
   Excel.Sheets sheets;
   Excel.Workbook workbook = null;
   object oMissiong = System.Reflection.Missing.Value;
   System.Data.DataTable dt = new System.Data.DataTable();
   wath.Start();
   try
   {
     if (app == null)
     {
       return null;
     }
     workbook = app.Workbooks.Open(excelFilePath, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, 
       oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong);
     //将数据读入到DataTable中——Start  
     sheets = workbook.Worksheets;
     Excel.Worksheet worksheet = (Excel.Worksheet)sheets.get_Item(1);//读取第一张表
     if (worksheet == null)
       return null;
     string cellContent;
     int iRowCount = worksheet.UsedRange.Rows.Count;
     int iColCount = worksheet.UsedRange.Columns.Count;
     Excel.Range range;
     //负责列头Start
     DataColumn dc;
     int ColumnID = 1;
     range = (Excel.Range)worksheet.Cells[1, 1];
     while (range.Text.ToString().Trim() != "")
     {
       dc = new DataColumn();
       dc.DataType = System.Type.GetType("System.String");
       dc.ColumnName = range.Text.ToString().Trim();
       dt.Columns.Add(dc);
 
       range = (Excel.Range)worksheet.Cells[1, ++ColumnID];
     }
     //End
     for (int iRow = 2; iRow <= iRowCount; iRow++)
     {
       DataRow dr = dt.NewRow();
       for (int iCol = 1; iCol <= iColCount; iCol++)
       {
         range = (Excel.Range)worksheet.Cells[iRow, iCol];
         cellContent = (range.Value2 == null) ? "" : range.Text.ToString();
           dr[iCol - 1] = cellContent;
       }
       dt.Rows.Add(dr);
     }
     wath.Stop();
     TimeSpan ts = wath.Elapsed;
     //将数据读入到DataTable中——End
     return dt;
   }
   catch
   {
     return null;
   }
   finally
   {
     workbook.Close(false, oMissiong, oMissiong);
     System.Runtime.InteropServices.Marshal.ReleaseComObject(workbook);
     workbook = null;
     app.Workbooks.Close();
     app.Quit();
     System.Runtime.InteropServices.Marshal.ReleaseComObject(app);
     app = null;
     GC.Collect();
     GC.WaitForPendingFinalizers();
   }
 }
 /// <summary>
 /// 使用COM，多线程读取Excel（1 主线程、4 副线程）
 /// </summary>
 /// <param name="excelFilePath">路径</param>
 /// <returns>DataTabel</returns>
 public System.Data.DataTable ThreadReadExcel(string excelFilePath)
 {
   Excel.Application app = new Excel.Application();
   Excel.Sheets sheets = null;
   Excel.Workbook workbook = null;
   object oMissiong = System.Reflection.Missing.Value;
   System.Data.DataTable dt = new System.Data.DataTable();
   wath.Start();
   try
   {
     if (app == null)
     {
       return null;
     }
     workbook = app.Workbooks.Open(excelFilePath, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, 
       oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong);
     //将数据读入到DataTable中——Start  
     sheets = workbook.Worksheets;
     Excel.Worksheet worksheet = (Excel.Worksheet)sheets.get_Item(1);//读取第一张表
     if (worksheet == null)
       return null;
     string cellContent;
     int iRowCount = worksheet.UsedRange.Rows.Count;
     int iColCount = worksheet.UsedRange.Columns.Count;
     Excel.Range range;
     //负责列头Start
     DataColumn dc;
     int ColumnID = 1;
     range = (Excel.Range)worksheet.Cells[1, 1];
     while (iColCount >= ColumnID)
     {
       dc = new DataColumn();
       dc.DataType = System.Type.GetType("System.String");
       string strNewColumnName = range.Text.ToString().Trim();
       if (strNewColumnName.Length == 0) strNewColumnName = "_1";
       //判断列名是否重复
       for (int i = 1; i < ColumnID; i++)
       {
         if (dt.Columns[i - 1].ColumnName == strNewColumnName)
           strNewColumnName = strNewColumnName + "_1";
       }
       dc.ColumnName = strNewColumnName;
       dt.Columns.Add(dc);
       range = (Excel.Range)worksheet.Cells[1, ++ColumnID];
     }
     //End
     //数据大于500条，使用多进程进行读取数据
     if (iRowCount - 1 > 500)
     {
       //开始多线程读取数据
       //新建线程
       int b2 = (iRowCount - 1) / 10;
       DataTable dt1 = new DataTable("dt1");
       dt1 = dt.Clone();
       SheetOptions sheet1thread = new SheetOptions(worksheet, iColCount, 2, b2 + 1, dt1);
       Thread othread1 = new Thread(new ThreadStart(sheet1thread.SheetToDataTable));
       othread1.Start();
       //阻塞 1 毫秒，保证第一个读取 dt1
       Thread.Sleep(1);
       DataTable dt2 = new DataTable("dt2");
       dt2 = dt.Clone();
       SheetOptions sheet2thread = new SheetOptions(worksheet, iColCount, b2 + 2, b2 * 2 + 1, dt2);
       Thread othread2 = new Thread(new ThreadStart(sheet2thread.SheetToDataTable));
       othread2.Start();
       DataTable dt3 = new DataTable("dt3");
       dt3 = dt.Clone();
       SheetOptions sheet3thread = new SheetOptions(worksheet, iColCount, b2 * 2 + 2, b2 * 3 + 1, dt3);
       Thread othread3 = new Thread(new ThreadStart(sheet3thread.SheetToDataTable));
       othread3.Start();
       DataTable dt4 = new DataTable("dt4");
       dt4 = dt.Clone();
       SheetOptions sheet4thread = new SheetOptions(worksheet, iColCount, b2 * 3 + 2, b2 * 4 + 1, dt4);
       Thread othread4 = new Thread(new ThreadStart(sheet4thread.SheetToDataTable));
       othread4.Start();
       //主线程读取剩余数据
       for (int iRow = b2 * 4 + 2; iRow <= iRowCount; iRow++)
       {
         DataRow dr = dt.NewRow();
         for (int iCol = 1; iCol <= iColCount; iCol++)
         {
           range = (Excel.Range)worksheet.Cells[iRow, iCol];
           cellContent = (range.Value2 == null) ? "" : range.Text.ToString();
           dr[iCol - 1] = cellContent;
         }
         dt.Rows.Add(dr);
       }
       othread1.Join();
       othread2.Join();
       othread3.Join();
       othread4.Join();
       //将多个线程读取出来的数据追加至 dt1 后面
       foreach (DataRow dr in dt.Rows)
         dt1.Rows.Add(dr.ItemArray);
       dt.Clear();
       dt.Dispose();
       foreach (DataRow dr in dt2.Rows)
         dt1.Rows.Add(dr.ItemArray);
       dt2.Clear();
       dt2.Dispose();
       foreach (DataRow dr in dt3.Rows)
         dt1.Rows.Add(dr.ItemArray);
       dt3.Clear();
       dt3.Dispose();
       foreach (DataRow dr in dt4.Rows)
         dt1.Rows.Add(dr.ItemArray);
       dt4.Clear();
       dt4.Dispose();
       return dt1;
     }
     else
     {
       for (int iRow = 2; iRow <= iRowCount; iRow++)
       {
         DataRow dr = dt.NewRow();
         for (int iCol = 1; iCol <= iColCount; iCol++)
         {
           range = (Excel.Range)worksheet.Cells[iRow, iCol];
           cellContent = (range.Value2 == null) ? "" : range.Text.ToString();
           dr[iCol - 1] = cellContent;
         }
         dt.Rows.Add(dr);
       }
     }
     wath.Stop();
     TimeSpan ts = wath.Elapsed;
     //将数据读入到DataTable中——End
     return dt;
   }
   catch
   {
     return null;
   }
   finally
   {
     workbook.Close(false, oMissiong, oMissiong);
     System.Runtime.InteropServices.Marshal.ReleaseComObject(workbook);
     System.Runtime.InteropServices.Marshal.ReleaseComObject(sheets);
     workbook = null;
     app.Workbooks.Close();
     app.Quit();
     System.Runtime.InteropServices.Marshal.ReleaseComObject(app);
     app = null;
     GC.Collect();
     GC.WaitForPendingFinalizers();
   }
 }

 /// <summary>
 /// 将excel中的数据导入到DataTable中
 /// </summary>
 /// <param name="sheetName">excel工作薄sheet的名称</param>
 /// <param name="isFirstRowColumn">第一行是否是DataTable的列名</param>
 /// <returns>返回的DataTable</returns>
 public DataTable ExcelToDataTable(string sheetName, bool isFirstRowColumn)
 {
   ISheet sheet = null;
   DataTable data = new DataTable();
   int startRow = 0;
   try
   {
     fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
     if (fileName.IndexOf(".xlsx") > 0) // 2007版本
       workbook = new XSSFWorkbook(fs);
     else if (fileName.IndexOf(".xls") > 0) // 2003版本
       workbook = new HSSFWorkbook(fs);
     if (sheetName != null)
     {
       sheet = workbook.GetSheet(sheetName);
     }
     else
     {
       sheet = workbook.GetSheetAt(0);
     }
     if (sheet != null)
     {
       IRow firstRow = sheet.GetRow(0);
       int cellCount = firstRow.LastCellNum; //一行最后一个cell的编号 即总的列数
       if (isFirstRowColumn)
       {
         for (int i = firstRow.FirstCellNum; i < cellCount; ++i)
         {
           DataColumn column = new DataColumn(firstRow.GetCell(i).StringCellValue);
           data.Columns.Add(column);
         }
         startRow = sheet.FirstRowNum + 1;
       }
       else
       {
         startRow = sheet.FirstRowNum;
       }
       //最后一列的标号
       int rowCount = sheet.LastRowNum;
       for (int i = startRow; i <= rowCount; ++i)
       {
         IRow row = sheet.GetRow(i);
         if (row == null) continue; //没有数据的行默认是null　　　　　　　
         
         DataRow dataRow = data.NewRow();
         for (int j = row.FirstCellNum; j < cellCount; ++j)
         {
           if (row.GetCell(j) != null) //同理，没有数据的单元格都默认是null
             dataRow[j] = row.GetCell(j).ToString();
         }
         data.Rows.Add(dataRow);
       }
     }
     return data;
   }
   catch (Exception ex)
   {
     Console.WriteLine("Exception: " + ex.Message);
     return null;
   }
 }