I have a generic dictionary (lets call ChildCollection ). I would like
to ensure that whenever a child is added to this collection
(SomeParent.Chi ldren.Add(new Child()), the parent of the child object
is set appropriately.
For some reason I would like to understand, the Add method of
System.Collecti ons.Generic.Dic tionary<Tkey, TValis not virtual. Can
anyone offer some advice on how to accomplish this. I would like to
avoid implementing all methods of the IDictionary<TKe y, TVal>
interface, just to append some code to the add method.
Your help is appreciated.
5  13320 
In C# it does not have to be virtual. You can "hide" (override) public
methods of base classes.
This works. The Add method of MyDictionary will be called.
private class MyDictionary<T1 , T2: Dictionary<T1, T2>
{
public new void Add(T1 key, T2 val)
{
// do something
base.Add(key, val);
}
}
static void Main(string[] args)
{
MyDictionary<st ring, stringmyDict = new MyDictionary<st ring,
string>();
myDict.Add("KEY ", "VALUE");
}
<mm******@gmail .comha scritto nel messaggio
news:11******** **************@ k78g2000cwa.goo glegroups.com.. .
>I have a generic dictionary (lets call ChildCollection ). I would like
to ensure that whenever a child is added to this collection
(SomeParent.Chi ldren.Add(new Child()), the parent of the child object
is set appropriately.
For some reason I would like to understand, the Add method of
System.Collecti ons.Generic.Dic tionary<Tkey, TValis not virtual. Can
anyone offer some advice on how to accomplish this. I would like to
avoid implementing all methods of the IDictionary<TKe y, TVal>
interface, just to append some code to the add method.
Your help is appreciated.
Laura T. <LT@NOWHERE.COM wrote:
In C# it does not have to be virtual. You can "hide" (override) public
methods of base classes.
That won't help much if anything refers to the dictionary as a plain
Dictionary<T1,T 2though.
Hidden methods are a source of bugs just waiting to happen, IMO. It's
important that you can do it occasionally, but usually because a base
class out of your control has added a method with the same name as your
derived class. I wouldn't recommend using it as a "pseudo-override".
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
John and Laura thank you both for your replies.
Laura, I have implemented the solution you suggested and it does
work.
John:
I agree this could be "a source of bugs waiting to happen". What
would be your recommendation as a solution to the problem?
On Feb 27, 12:36 pm, Jon Skeet [C# MVP] <s...@pobox.com wrote:
Laura T. <L...@NOWHERE.C OMwrote:
In C# it does not have to be virtual. You can "hide" (override) public
methods of base classes.
That won't help much if anything refers to the dictionary as a plain
Dictionary<T1,T 2though.
Hidden methods are a source of bugs just waiting to happen, IMO. It's
important that you can do it occasionally, but usually because a base
class out of your control has added a method with the same name as your
derived class. I wouldn't recommend using it as a "pseudo-override".
--
Jon Skeet - <s...@pobox.com >http://www.pobox.com/~skeet Blog:http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
<mm******@gmail .comwrote:
John and Laura thank you both for your replies.
Laura, I have implemented the solution you suggested and it does
work.
John:
I agree this could be "a source of bugs waiting to happen". What
would be your recommendation as a solution to the problem?
Well, IDictionary<K,V doesn't actually have many methods - it wouldn't
be hard to have a member which is a "normal" Dictionary<K,Va nd proxy
all calls to that, just doing the extra bit first in Add.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
True. But that's the price of inheritance I guess.
You can always abuse the design of you really want to.
Once I did have to use reflection at runtime to "override" some method
implementations because of the abuse.
"Jon Skeet [C# MVP]" <sk***@pobox.co mha scritto nel messaggio
news:MP******** *************** *@msnews.micros oft.com...
Laura T. <LT@NOWHERE.COM wrote:
>In C# it does not have to be virtual. You can "hide" (override) public
methods of base classes.
That won't help much if anything refers to the dictionary as a plain
Dictionary<T1,T 2though.
Hidden methods are a source of bugs just waiting to happen, IMO. It's
important that you can do it occasionally, but usually because a base
class out of your control has added a method with the same name as your
derived class. I wouldn't recommend using it as a "pseudo-override".
--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too
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