[DUG] Creating an object at run time.

[Kyley Harris]

They dont need to. DFM use read component and you pass an existing
instance.. ie TFORM as the top layer. it then uses the runtime information
of the instance to stream the data. ie.. a button on the form as a property
has runtime information, but its not registered with GetClass.. the only
difference is that you need global lookup. the class info is in memory,
just not in the lookup list.

Have fun.



On Mon, Jul 16, 2012 at 5:45 PM, David O'Brien <Dave at iccs.co.nz> wrote:

> Thanks, Oh well... I understand, but I don’t really know what classes will
> be used, guess I’ll just have to register everything L. I would have
> thought the standard VCL controls would have been sorted though...****
>
> ** **
>
> ** **
>
> *From:* delphi-bounces at listserver.123.net.nz [mailto:
> delphi-bounces at listserver.123.net.nz] *On Behalf Of *Kyley Harris
> *Sent:* Monday, 16 July 2012 5:35 p.m.
>
> *To:* NZ Borland Developers Group - Delphi List
> *Subject:* Re: [DUG] Creating an object at run time.****
>
> ** **
>
> David,
>
> a basic test on a blank form shows that the following code doesn't work
> unless registerclass is called first (of course you'd only do this 1 time).
>
> clearly they are not registering these classes by default for streaming.
> you will probably find that the Delphi IDE registers them all internally
> for DFM creation, but they haven't done it by default for end runtime code.
>
> begin
>   RegisterClass(TButton);
>   with TComponentClass(FindClass('TButton')).Create(self)  as tbutton    do
>   begin
>      top := 10;
>      left := 10;
>      caption := 'hello';
>      width := 100;
>     parent := self;
>   end;****
>
> On Mon, Jul 16, 2012 at 12:41 PM, David O'Brien <Dave at iccs.co.nz> wrote:**
> **
>
> Very frustrating, I'm getting "Class TButton not Found" with the below
> code. Everything in the uses clause is correct: I have a Tbutton on the
> form at design time. The form is in a .bpl if that will make a
> difference?
>
> // Simplified...
> Uses ..., StdCtrls, ...
> Var
>   o: TComponent ;
>   ot: String ;
> begin
>       ot := 'TButton' ;
>       o := TComponentClass(FindClass(ot)).Create(nil); <--- Class
> TButton Not Found
> end ;****
>
>
> -----Original Message-----
> From: delphi-bounces at listserver.123.net.nz
> [mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Todd Martin
> Sent: Friday, 13 July 2012 4:27 p.m.****
>
> To: NZ Borland Developers Group - Delphi List
> Subject: Re: [DUG] Creating an object at run time.****
>
> b := TComponentClass(FindClass('TButton')).Create(nil);
> propinfo := GetPropInfo(b.classinfo,'left'); SetOrdProp(b,propinfo,100);
>
> > I want to create an object at runtime given a string with the object
> type. Is this possible or do I need to do a whole pile of if then
> else's? There is a limited number of different objects that need to be
> created. I then want to access the created objects properties by name
> and assign methods.
> >
> > This is not for oleobjects, but VCL controls.
> >
> > i.e.
> > b := CreateObject('TButton') ;
> > b.GetField('left') := 100 ;
> > ...
> >
> > Help on any of these would be appreciated.
> >
> > Cheers,
> > Dave.
> >
> >
> > _______________________________________________
> > NZ Borland Developers Group - Delphi mailing list
> > Post: delphi at listserver.123.net.nz
> > Admin: http://delphi.org.nz/mailman/listinfo/delphi
> > Unsubscribe: send an email to delphi-request at listserver.123.net.nz
> > with Subject: unsubscribe
>
>
> _______________________________________________
> NZ Borland Developers Group - Delphi mailing list
> Post: delphi at listserver.123.net.nz
> Admin: http://delphi.org.nz/mailman/listinfo/delphi
> Unsubscribe: send an email to delphi-request at listserver.123.net.nz with
> Subject: unsubscribe
>
> _______________________________________________
> NZ Borland Developers Group - Delphi mailing list
> Post: delphi at listserver.123.net.nz
> Admin: http://delphi.org.nz/mailman/listinfo/delphi
> Unsubscribe: send an email to delphi-request at listserver.123.net.nz with
> Subject: unsubscribe****
>
>
>
>
> --
> Kyley Harris
> Harris Software
> +64-21-671-821****
>
> _______________________________________________
> NZ Borland Developers Group - Delphi mailing list
> Post: delphi at listserver.123.net.nz
> Admin: http://delphi.org.nz/mailman/listinfo/delphi
> Unsubscribe: send an email to delphi-request at listserver.123.net.nz with
> Subject: unsubscribe
>



-- 
Kyley Harris
Harris Software
+64-21-671-821
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://listserver.123.net.nz/pipermail/delphi/attachments/20120716/cc8771b2/attachment.html