Retrive data using disconnetcted architecture

Public DataSet GetData()
        {
            String connectionstring = "your connection string";
            using (SqlConnection connection = new SqlConnection(connectionstring))
            {
                if (connection.State == ConnectionState.Closed)
                    connection.Open();
                SqlCommand command = new SqlCommand("Select * from tablename where colName = value", connection);
                SqlDataAdapter adapter = new SqlDataAdapter(command);
                DataSet ds = new DataSet();
                adapter.Fill(ds);
                if(connection.State == ConnectionState.Open)
                    connection.Close();
                return ds;
            }
        }