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Unlimited undo/redo?

Posted on 2000-04-09
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Last Modified: 2010-04-04
I need source code, explaining who can i add unlimiited undo/redo functionality to my program. I'm using TRichEdit.

Thanks.

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Question by:pin_plunder
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11 Comments
 
LVL 1

Expert Comment

by:Edo082297
ID: 2698222
Hello

Check out the Command design pattern in _Design Patterns_ by Richard Gamma et al (the 'Gang of Four', or GOF).

The concept is that you want to encapsulate user actions as objects and push them onto a stack. Undoing an action involves reversing the operation (obviously) and keeping a current index on the stack.

Have fun

Edo
0
 
LVL 17

Expert Comment

by:inthe
ID: 2698252
HI,
i think you will be wanting this because as you may know delphis standard trichedit only has one level of undo whereas richedit2 has multiple undo/redo:

ftp://ftp.cdrom.com/pub/delphi_www/ftp/d30free/riched98.zip

Rich edit control with extended capabilities. Extra formatting properties (highlight, indices, line spacing and so on), URL detection, multilevel undo/redo, support for Unicode strings. Requires RICHED20.DLL


0
 

Author Comment

by:pin_plunder
ID: 2699039
could you post the link again, i believe it's not ok.. thanks!
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LVL 10

Expert Comment

by:Lischke
ID: 2699414
Hi pin_plunder,

what about a real implemetation? Download my Unicode edit control from www.lischke-online.de/Unicode.html. There I have implemented unlimited undo/redo and you can ask me here if you have problems.

Ciao, Mike
0
 
LVL 17

Accepted Solution

by:
inthe earned 120 total points
ID: 2701173
mike ,
you have been busy again :o)

pin_plunder,
here another link :

http://sunsite.icm.edu.pl/delphi/ftp/d30free/riched98.zip
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LVL 10

Expert Comment

by:Lischke
ID: 2701695
I can tell you Barry :-)... in particular with my new E-E sponsored scanner I got today. There's no driver for W2K for this thing. Unbelievable...

Sorry for being off topic.

Ciao, Mike
0
 
LVL 17

Expert Comment

by:inthe
ID: 2702387
How typical for a free gift ,
maybe idea to tell customer services maybe they can send a different one ..
nevermind ..the visor cant do much also as its only "solo" version,theres no link to pc or internet :o(

0
 
LVL 3

Expert Comment

by:darinw
ID: 2702625
Mike & inthe:

Another Expert has already posted a question in CS about the Scanner being Win98 only :(

I apologize for the limitations of the free gift we sent you. I have forwarded the concerns that the other Expert had, which were very well communicated, to the rest of the staff. As I told him/her, it may not make a difference: flexible often means expensive.

Let me see if I can find the link to the other question. You guys can post there your comments there if you'd like.

darinw
Customer Service
0
 
LVL 3

Expert Comment

by:darinw
ID: 2702629
Got it:

http://www.experts-exchange.com/jsp/qShow.jsp?ta=commspt&qid=10324707 

Sorry for the off-topic posts pin_plunder.

darinw
Customer Service
0
 
LVL 10

Expert Comment

by:Lischke
ID: 2703225
Thank you darinw, I did the same like Pino (actually I still have installed a Win98 partition for test reasons, as Pino said, most experts are developer...).

pin_plunder, sorry again for that off-topic stuff. How did you came forward with the undo/redo stuff? Have you downloaded my Unicode edit control? Do you need more help?


Ciao, Mike
0
 

Author Comment

by:pin_plunder
ID: 2706211
yeah, everything's ok. I've downloaded it, but couldn't test it right now, so ...
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