> ... and I probably should have mentioned, the implementation of Tx.Create
> should be
>
> constructor Tx.Create;
> begin
> inherited Create;
> end;
[Tested in D4]
Whilst this may stop the code reaching the constructor the compiler will
still compile a line in a different unit
x := TDescendant.Create;
even if the descendant does not declare a constructor... The program will
run using the code of the constructor one further step up the class-tree
producing unpredictable results. Hence you're back to a run-time ident
problem with unpredictable results... Better to make the public constructor
produce an exception and have a private constructor perform valid construction
from the class method that validates the construction process.
TSpam = class
private
constructor _PrivateCreate;
public
constructor Create;
end;
constructor TSpam._PrivateCreate;
begin
inherited Create;
// actual constructor code...
end;
constructor TSpam.Create;
begin
inherited Create;
// raise an exception with predictable results...
raise Exception.Create("You cannot instantiate an instance of '+ClassName);
end;
--
Aaron Scott-Boddendijk
INTAZ Limited
+64 7 838 3371 Voice
+64 7 838 3372 Fax
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