2013/9/29 Sven Barth <pascaldra...@googlemail.com>
>
> I would suggest you to add an additional protected virtual method to
> TTree<> which is called from TTree<>.Clone and you override that in your
> descendant classes.
>
Could
you please give an example how to do this? I tried the following:
=== code start ===
function TTree.DoClone: TTree; //protected, virtual
begin
Result := TSelfClass(Self.ClassType).Create(Data, FParent);
end;
function TTree.Clone: TTree;
var
node: TTree;
begin
Result := DoClone;
node := FirstChild;
while node <> nil do begin
node.Clone.Remove(Result);
node := node.NextSibling;
end;
end;
=== code end ===
However, this does not work, because it seems that I cannot make any
generic method virtual! In TIntTree, I have to write:
function TIntTree.DoClone: TIntTree;
As it is not possible to write TTree outside of the generic definition.
Regards,
Xiangrong
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