CODEWITHSUNDEEP
delphicollectionsdelphi-xe2
JustMe
JustMe

Reputation: 2383

What to do when I need to call owner owner's owner method?

I've got TbsManager class which expose Load method like:

 TbsManager = class(TComponent)
 private
   FItems: TbsItems;  
 public
   procedure Load(Item: TbsItem);

The TbsItem is a TCollectionItem and it's owned by TbsItems:

TbsItem = class(TCollectionItem)
TbsItems = class(TCollection)

I want my TbsItems to have the Load method (which is in the onwer's owner class) and this is how I achieved it:

procedure TbsItem.Load;
begin
  TbsManager(TbsItems(GetOwner).Owner).Load(Self);
end;

I'm not sure if I've done it right. Is it a safe code?

Upvotes: 1

Views: 304

Answers (1)

David Heffernan
David Heffernan

Reputation: 613322

If your design mandates that hierarchy then your code is reasonable. I'd modify it to use checked casts, with the as operator. These will raise runtime errors if the classes are not of the required type:

((GetOwner as TbsItems).Owner as TbsManager).Load(Self);

Upvotes: 1

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