如 123424234234，读取到DataTable中变成了1.23424E+11
方法是这样的 public static DataTable GetDataTableBySheet(string excelFile, string sheetName)      {          string connStr = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;data source={0};Extended Properties='Excel 8.0;HDR=YES;IMEX=1;'"                          , excelFile);          string sql = string.Format("select * from [{0}$]", sheetName);          OleDbConnection cn = new OleDbConnection(connStr);          OleDbCommand cm = new OleDbCommand(sql,cn);          OleDbDataAdapter da = new OleDbDataAdapter(cm);          DataTable dt = new DataTable();          try          {              cn.Open();              da.Fill(dt);              return dt;          }          catch (OleDbException)          {              throw;          }          finally          {              if (cn != null)              {                  cn.Close();              }          }      }