Solved

Access an owner procedure from a TPersistent class

Posted on 2002-03-28
18
311 Views
Last Modified: 2013-11-23
I use in my component a TPersistent class . Here, before invalidate the owner, I need to access an owner procedure ( alike Prepare ).
How can I do that ?
0
Comment
Question by:ginsonic
18 Comments
 
LVL 1

Expert Comment

by:Alone
ID: 6903286
If your owner class and TPersistent descedant are in same unit, you can call all methods directly, because they are treated as "friendly" classes
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6904465
Are you sure ?

Prepare; // [Error] test.pas(272): Undeclared identifier: 'Prepare'
FOwner.Invalidate;

Same result for FOwner.Prepare;
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6904469
And please ... don't put an answer directly . Type a comment and if I will be satisfy I will accept it as answer .
So the question will not be lock for others experts .
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 14

Expert Comment

by:AvonWyss
ID: 6904532
If you do know what type the owner is, you can typecast so that you can access the identifiers. Is this what you need?
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6904853
Can you give me a sample ?

My component ( the owner ) is a TCustomControl descendent .

From TPersistent descendent I wish to call something alike :

FOwner.Prepare;
FOwner.Invalidate;
0
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 6909718
umm...

(FOwner as TCustomControl).Invalidate;

I don't think a TCustomControl has a Prepare method... or does it?
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6910147
Prepare is my own procedure . I need to call Prepare before invalidate .

Nick

BTW, FOwner.Invalidate work too .
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6936032
No solution here :(
0
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 6936057
Do you know the class for the owner? Let's say it is TMyCustomOwnerClass

then all you need to do is TMyCustomOwnerClass(FOwner).Prepare;
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6936488
Have tried your suggestion :

TDBGrid(FOwner).Prepare; // in my case

No success :(
0
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 6940947
but TDBGrid does not have a method called Prepare! where did you declare the Prepare method? Any ideas?
0
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 6940949
some codes might be useful
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6941107
I work to a DBGrid that accept images for background . In same time can be set to transparent or semi-transparent.

Before invalidate my grid, I need to PREPARE ( OWN procedure ) the background ( declared into protected area ).

But in same time , when set couple properties (TPersistent descendents) I need to Invalidate . But before this, still I need to call Prepare . So ...

How can I call from a TPersistent an owner procedure ( OWN declared ) .
0
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 6941141
Umm... I need to know who owns Prepare :)
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6941855
Prepare is a protected procedure of my TgnDBGrid descendent from TCustomDBGrid .

So the owner is TgnDBGrid .
0
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 6943637
then you should do

TgnDBGrid(Owner).Prepare;
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6943923
Already tried :(
0
 
LVL 14

Accepted Solution

by:
DragonSlayer earned 50 total points
ID: 6943940
umm... either

1. Make it public

2. Create a new class

type
  THackMyDBGrid = class(TgnDBGrid)
  public
    procedure Prepare; // change visibility
  end;

THackMyDBGrid(Owner).Prepare;



:)
0

Featured Post

Secure Your Active Directory - April 20, 2017

Active Directory plays a critical role in your company’s IT infrastructure and keeping it secure in today’s hacker-infested world is a must.
Microsoft published 300+ pages of guidance, but who has the time, money, and resources to implement? Register now to find an easier way.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…
Are you ready to implement Active Directory best practices without reading 300+ pages? You're in luck. In this webinar hosted by Skyport Systems, you gain insight into Microsoft's latest comprehensive guide, with tips on the best and easiest way…

733 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question