public class DBClass
     ... 
     public Function GetTable(Sql as String) as DataTable
         Dim Adp as new SqlDataAdapter(sql,CnStr)
         Dim  Dt as New DataTable
         Adp.Fill(Dt)
         Return Dt
     End Function
 
End Class
.....
....
Dim cs as new DBClass
Dim Ds as new DataSet("TestDS")
Ds.Tables.Add(cs.getTable("Select * from Table1"),"Table1")
...