Re: Child objects inheriting property values

"Moreover, assigning field values of a base class to its subclass in
a constructor feels awkward. A good compiler should disallow it."  

If any .NET compiler disallowed it ASP.NET wouldn't work! :) 
At least the older ASP.NET Web Application code-behind model.  In the
code behind you declare all of the controls while the .aspx page
instantiates them.  Quite awkward and convoluted resulting in a page
that can compile but if you forget to add the control to the page it
crashes at runtime.

-----Original Message-----
From: Discussion of development on the .NET platform using any managed
language [mailto:[email protected]] On Behalf Of Peter
Obiefuna
Sent: Wednesday, November 21, 2007 9:40 PM
To: [email protected]
Subject: Re: [DOTNET-CLR] Child objects inheriting property values

Using inheritance is semantically wrong since a Column 'IS A' record is
not
correct. Moreover, assigning field values of a base class to its
subclass in
a constructor feels awkward. A good compiler should disallow it.
Again, the class order in your question appears reversed to me (I expect
a
column collection to exist before a record does) but I'll just answer
your
question narrowly. Here's my solution to that problem.
=======================================

class Column{

    private char delimiter;
    public Column(){
        // first, set parent record;
        // then ...
        this.delimiter = ParentRecord.Delimiter;
    }
    public Record ParentRecord { get; set; }
    public char Delimiter { get; set; }
}

class Record{
    private char delimiter = '^';
    public Record(){

    }
    private Column[] columns;
    public char Delimiter {get; set;}

}

--------------------------------------------------
From: "Adrian Martin" <[email protected]>
Sent: Tuesday, November 20, 2007 6:28 AM
To: <[email protected]>
Subject: Re: [DOTNET-CLR] Child objects inheriting property values

>        class Column : Record
>        {
>                public Column()
>                {
>                        this.Delimeter = base.Delimeter;
>                }
>        }
>
>
>
>
>
>
>
> -----Original Message-----
> From: Discussion of development on the .NET platform using any managed
> language [mailto:[email protected]] On Behalf Of Brady
> Kelly
> Sent: 20-November-2007 10:10
> To: [email protected]
> Subject: Child objects inheriting property values
>
> I have a hierarchy of objects that share some attributes, e.g. both my
> parent Record and Column objects have a columnDelimiter property.  I
> want
> this property on the Column object to default to the same property on
> the
> Record object, until specified on the Column object.  What is the best
> way
> to go about this?  I could give each Column a reference to the Record
it
> belongs to, but this seems not quite right to me.  My other option is
to
> have the Record act as a ColumnFactory, setting the columnDelimiter
> value on
> each Column it creates, until a set accessor on Column optionally
> overrides
> that default value.
>
>
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