C#操作EXCEL文件另一个问题

        public DataSet ExcelToDS(string path)

        {

            string connStr = "Provider=Microsoft.Jet.OLEDB.4.0;"

                + "DataSoure=" + path + ";"

                + "Extend Properties=Excel 8.0;HDR=NO;IMEX=1";

            OleDbConnection conn = new OleDbConnection(connStr);

            conn.Open();

            

            string cmdStr = "select * from [sheet1$]";

            OleDbDataAdapter adapter = new OleDbDataAdapter(cmdStr, conn);

            DataSet ds = new DataSet();

            adapter.Fill(ds);

            return ds;

        }

程序跑到conn.OPen();的时候就发生异常；
异常信息：
未处理System.Data.OleDb.OleDbException
  HResult=-2147467259
  Message=找不到可安装的 ISAM。
  Source=Microsoft JET Database Engine
  ErrorCode=-2147467259
  StackTrace:
       在 System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)
       在 System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)
       在 System.Data.ProviderBase.DbConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
       在 System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup, DbConnectionOptions userOptions)
       在 System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
       在 System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
       在 System.Data.ProviderBase.DbConnectionInternal.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
      &nbs