Return types

[bpayne111]

When overriding the clone method of an arraylist should i let it Return Object as default or change this to MyClassName?
i have a feeling im supposed to leave it as object but i dont understand why...

any thoughts, ideas and crude remarks appreciated

 

[AndreRyan]

Either will probably work becuase object can be turned into MyClassName and MyClassName can be turned into object

 

[bpayne111]

yes, but i feel there is some generally accepted principle i am missing in this instance
ie. sender is always object in an event, this is ovious but why not make it the same type as the calling object? (in this case could delegates be involved... ill save those questions for another day)

 

[AndreRyan]

Becuase events can be triggered by different classes with no real connection to each other(ie. MyEvent(Sender as Object,e as ...), the sender could be a windows control or a class which are not neccessarily related(derived from the same base)). Youll probably want to return it as an Object becuase if its a clone, youll want it programmer to be able to attach the clone as a derived object

 

[Divil]

Why would you inherit from ArrayList? If you need to make a collection of your own type, you should inherit from CollectionBase and provide your own accessor and add, remove functions etc.

 

[bpayne111]

Aha, once again ive made a foolish mistake...
This brings me to another question.. suprise suprise

Public Overrides Function Clone() as Object

Return Me

End Function

Would this return a deep copy? How do i return a shallow copy?

 

[Nerseus]

You need to create a new instance of your class type (whatever it is), and set all properties of the new class to the current instance (Me). Return the new instance in the Clone function.

If all of your private fields are value types, you can use Me.Clone() instead. If you have ANY fields that are objects, youll have to do it manually.

-Nerseus

 

[bpayne111]

isee what i need to do now but does that mean i define what a shallow copy is in this method myself?

thanks

 

[TechnoTone]

Originally posted by bpayne111
Aha, once again ive made a foolish mistake...

Making mistakes isnt foolish... not learning from them is.

 

[Divil]

Could it be that a value type would be more suited for your needs, in this instance? That way when you pass them only a copy is passed.

 

[Nerseus]

To be clearer (in case you didnt know what divil meant), could you make your class a struct instead? Then using asignment would make an actual copy instead of just assigning the pointer to the same instance. Also, passing a struct ByRef would pass a copy of the object rather than just a reference.

-Nerseus

 

[bpayne111]

I see what you mean... I think it could be possible
So if i passed a structure instead of my class itself the properties would not be altered?
I need to keep it as an object because i need to inherit from it for the UIs class
i also have trouble understanding the difference in types and objects. ive read a little on it but i still feel kinda confused about it.

you guys are great thanks