You can do it at the Method level in delphi by declaring {$WRITEABLECONST
ON} which esentially makes the const a static for the scope of the method
it's delared in. I've never checked to see if it works between multiple
instances of a class as I've generally only used it for singletons - like
I've pasted in below.
Nahum.
-----------------
{$WRITEABLECONST ON}
class function TMouseCursorManager.Inst(const bFreeInstance : boolean =
False) : TMouseCursorManager;
const
AMouseCursorManager : TMouseCursorManager = nil;
begin
if bFreeInstance then begin
if assigned(AMouseCursorManager) then begin
AMouseCursorManager.fAllowFree := True;
FreeAndNil(AMouseCursorManager);
end;
Result := nil;
end
else begin
if not assigned(AMouseCursorManager) then begin
AMouseCursorManager := TMouseCursorManager.CreateInstance;
AMouseCursorManager.Setup;
end;
Result := AMouseCursorManager;
end;
end;
{$WRITEABLECONST OFF}
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On
> Behalf Of Paul Heinz
> Sent: Friday, 21 February 2003 14:35 p.m.
> To: Multiple recipients of list delphi
> Subject: RE: [DUG]: Delphi shared class data members?
>
>
> Bob wrote:
>
> > Horrors! I'm in the process of familiarising myself with the new
> > VB for .NET. In all fairness I must say its not too bad at all,
> > though I've been having quiet gloats at the "new" language
> > features ("ha! - had that in Delphi 1" etc.). I hadn't
> > discovered any capabilities I wasn't familiar with in Delphi,
> > until I came across VB's Shared class data members.
> >
> > They work like this: a data member is declared as Shared (scope
> > can be specified normally) and all instances of the class and its
> > descendants share the same variable - a bit like having a global
> > with class scope. I can see how they'd be useful in some
> situations.
> >
> > Quelle horreur, out-gunned by VB! I can't find an equivalent in
> > Delphi - this is even worse than losing the Americas cup! Can
> > anyone put me out of my misery and point out a feature of
> > deepest, darkest Delphi where we can do the same?
>
> Actually, C++ has them too since day 1 - they're called
> static or class
> members in C++.
>
> Delphi has class functions and class methods, but not class members.
>
> You could 'fake' them by having a class function which
> returns an object
> instance which was kept in a private (i.e. implementation
> section) unit
> variable.
>
> In fact, we use this idiom in a number of places - the class
> function even
> operates as a singleton factory i.e. it creates an instance
> the first time
> it's called and returns that instance thereafter.
>
> This is sometimes quite handy for avoiding for resolving tricky
> initialization order issues between cooperating classes in
> different units.
>
> TTFN,
> Paul.
>
> --------------------------------------------------------------
> -------------
> New Zealand Delphi Users group - Delphi List -
> [EMAIL PROTECTED]
> Website: http://www.delphi.org.nz
> To UnSub, send email to: [EMAIL PROTECTED]
> with body of "unsubscribe delphi"
> Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/
>
---------------------------------------------------------------------------
New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED]
Website: http://www.delphi.org.nz
To UnSub, send email to: [EMAIL PROTECTED]
with body of "unsubscribe delphi"
Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/
