ExecuteReader: Connection property has not been initialized.

DatabaseClass dqwb = new DatabaseClass();
            dqwb.dbConnection("(local)", "General", "DWSS123-PC", "dwss123");
         

          
           
            //SqlConnection myConnection1 = new SqlConnection("Server=(local);Database=General;Trusted_Connection=True;");
            //myConnection1.Open();
           
            //SqlCommand com;
            string str;
            
            try
            {
                //com = new SqlCommand();


                SqlCommand com = new SqlCommand("select YearLabel from dbo.CompanyYear");
                dqwb.openConnection();
                //com.CommandText = "select YearLabel from dbo.CompanyYear";

                SqlDataAdapter sda = new SqlDataAdapter(com);
                SqlDataReader reader = com.ExecuteReader();
                DataTable dt = new DataTable();
                DataSet ds = new DataSet();
                ds.Tables.Add(dt);
}








 public void dbConnection(string ProjectName112, string databasenameName112, string user12,string pass12)
        {
            string strProject = ProjectName112; //Enter your SQL server instance name
            string strDatabase = databasenameName112; //Enter your database name
            string strUserID = user12; // Enter your SQL Server User Name
            string strPassword = pass12; // Enter your SQL Server Password



            //string strProject = a; //Enter your SQL server instance name
            //string strDatabase = b; //Enter your database name
            //string strUserID = c; // Enter your SQL Server User Name
            //string strPassword = d; // Enter your SQL Server Password

            string strconn = "data source=" + strProject + ";database=" + strDatabase + ";Persist Security Info=True;User ID=" + strUserID + ";Password=" + strPassword + ";";
           
            conn = new SqlConnection(strconn);

           
        }