How to pull inherited methods from a class object?

Question

C++ / C#

Hello, I'm doing an assignment on polymorphism in one of the online courses and everything would be fine, but I ran into the problem (as it seems to me of the syntax) of how to extract inherited methods from an object in this situation:

public class DbCommand
    {
        public DbCommand(object DbConnection)
        {

            Console.WriteLine("Db_COMMAND is online...\n");

            if (DbConnection is null)
            {
                throw new ArgumentNullException(nameof(DbConnection));
            }
        }

        public void Executerrr()
        {

            /*

            Here must be an object that should "discover" methods OpenConnection() and CloseConnection()
            but I cannot figure out what kind of object should I put inside Execute() method...

            */
        
        }

    }


    public abstract class DbConnection
    {
     
        public string _ConnectionString { get; set; }
        public TimeSpan Timeout { get; set; }

        public DbConnection(string connectionString)
        {
            _ConnectionString = connectionString;
        }

        public abstract void OpenConnection();
        public abstract void CloseConnection();
    }


    public class SqlConnection : DbConnection
    {
        public SqlConnection(string connectionString) : base(connectionString)
        {
        }

        public override void CloseConnection()
        {
            Console.WriteLine("SQL connenction Closed");
        }

        public override void OpenConnection()
        {
            Console.WriteLine("SQL connenction OPEN");
        }
    }

    public class OracleConnection : DbConnection
    {
        public OracleConnection(string connectionString) : base(connectionString)
        {
        }

        public override void CloseConnection()
        {
            Console.WriteLine("ORACLE connenction Closed");
        }

        public override void OpenConnection()
        {
            Console.WriteLine("ORACLE connenction OPEN");
        }
    }

static void Main(string[] args)
        {
// simple example:

            var SQLconn = new SqlConnection("sql ready");
            var ORACLEconn = new OracleConnection("oracle ready");

            SQLconn.OpenConnection();
            SQLconn.CloseConnection();

            ORACLEconn.OpenConnection(); // works fine
            ORACLEconn.CloseConnection(); // works fine
            
// here's a more complicated example

            var start = new DbCommand(new OracleConnection("oracle ready"));

            start.Executerrr();
}

It is necessary for me that if I give an object of the OracleConnection class - when the method is launched Executerrr(), the methods for the OracleConnection are executed and, accordingly, if the SqlConenction - the phrases for Sql are displayed. It just object DbConnectiondoes not see abstract methods (and according to my calculations, it seems like it should)))).

Thank you!

Answer 1

You must explicitly specify the class.

public DbCommand(object DbConnection) -> public DbCommand(DbConnection DbConnection)