Is there any difference between using vcl components in Delphi and WinApi functions to create gui application.
#Azad I think there are 2 big differences: the first is the ease of use of the VCL that enables you to drag and drop controls on a form (window), change its properties and assign events, giving you high productivity in the development of the GUI.
The other big difference is the size of the final application, if you create an application using only WINAPI calls, your final application will be smaller than using the VCL.
I recommend you see the project KOL (KOL - Key Objects Library is a set of objects to develop power (but small) 32 bit Windows GUI applications using Delphi but without VCL (or Free Pascal). It is distributed free of charge, with source code.).
(source: kolmck.net)
Almost all real-world Delphi applications use the VCL, and also make OCCASIONAL direct calls to the Win32 API. The VCL framework calls Win32 calls, in the end, anyways. So, you will almost always be using both.
The guy who mentioned KOL is suggesting yet another "middle" layer, because going direct is sublimely painful.
Microsoft has (in historical order), MFC, and ATL for C++, and .NET for the C#/VB.net language, as "framework" layers that live between your application and the raw Win32 API, for their MS Visual Studio products.
People who write anything more complicated than Notepad.exe going straight to the "metal" (Win32 API raw) are rare. So, it's harder, it takes longer to learn, and do everything. And in the end, it's not significantly faster or better. If you really need to be small (like you are writing a virus) maybe you might want to go Win32 native.
The VCL is a complete framework wrapping the Windows API and insulating the developer from the gory details, making it so much easier to develop Delphi applications.
You gain big in productivity and compatibility over Windows version changes...
Well, sure, VCL requires a Borland compiler. The Win32 API works for any language. The point of using a GUI class library, like VCL, is to make the effort of creating a GUI enabled program easier. Doing so using only Win32 is quite punishing.
time, time and then even more time.
You use WinAPI to do things that VCL is not "able" to do.
Related
I have inherited a legacy app written in C++ (VS2003) MFC that was not updated in years.
I have limited experience in C++, being mainly a Delphi developer. All other apps of the company are written in Delphi.
Going forward, I see a few choices:
1) Keep the app as is and become a C++ MFC developer. But I don't like the idea of using an outdated technology (MFC) for years to come, trying to keep up with new Windows versions and UI standards. It somehow feels like making several steps backwards and I don't think this is the best way to go (?)
2) Convert the app to any modern UI technology offered with C++ and become a C++ developer, but at least using modern technology. Might be a lot of work, not sure.
3) Rebuild the app from scratch in Delphi, where I will be a lot more productive thinking about the future. It's a lot more work right now, but it might pay off later.
Obviously, I personally prefer 3) but I would like to know from your experience which way is the best for the product.
It's a long term decision to make and I will have to stick with it, therefore I don't want to rush into one direction.
(I have intentionally not tagged this question as C++, trying to get answers from Delphi developers in similar situations)
EDIT:
Thanks to all for your answers.
After learning that it is possible to switch to C++ Builder with a MFC application, this seems to be the best solution.
It combines the least amount of modifications to the current app with the possibility to go forward using the VCL for future GUI improvements.
EDIT2:
It's not possible to combine MFC and VCL in one app, therefore C++ Builder won't be an option. (thanks David for pointing this out)
In general everything depends on how complex the application's logic is and what is the projected life time of the application. If it requires maintenance for another 20 years, then
I'd rewrite the UI in Delphi and move the business logic into C++ DLL (for beginning and possibly rewrite it in Delphi either). Then it can turn that the application can be maintained this way for another 10 years and relatively easily ported to other platforms if needed (less work would be required).
This is a hard question to answer generically. Can you provide any more information about your specific app? What sort of technologies does it use? How separated is the UI from underlying layers and logic?
Some general-ish points though:
Rewriting an app is generally a bad idea, for the following reasons:
It's surprisingly hard to get an accurate idea of the requirements. You're sure you know what it does (after all, it's right there in front of you!), but then you release your rewritten app and you get complains that functionality you didn't know was there is missing, that functionality is harder to access if you've changed something, etc.
It introduces bugs. The code, especially if it's old, is full of bugfixes, tweaks, etc. You will lose all that if you rewrite, especially if it's a different language and you can't reuse any code at all.
When using a different UI layer (MFC to something else) separating the UI can be very hard if the app wasn't written well in the first place. You will probably end up doing a lot of refactoring, even if you don't do a complete rewrite and simply move from MFC to 'something else'.
MFC is kept up to date (ish) - there is a MFC Ribbon control, for example, as well as modern controls and Windows 7 support. The least amount of work, probably, would be to upgrade to a modern version of Visual C++ and become a C++ developer. However, you're quite right that MFC is an old technology and is unpleasant to use, not only because of its design, but also because modern form designers etc are great to use.
You're a Delphi developer. Without rewriting the entire thing, you could consider migrating to C++Builder. Consider this:
You can use old versions of MFC with C++Builder. I've never done this, since the VCL is miles ahead, but it's possible and there are a number of people who do it. Check out this forum, for example. (Credit for that link: this thread.)
Once you have your app compiling and working with C++Builder, you can start migrating to the VCL. As a Delphi developer you'll find using this, even with C++, very familiar. It's the same form designer of course, and using it from C++ is pretty simple - it's a different language but code is often line-for-line translatable. Everything you're used to (DFM files, units, event handlers, etc) all translate.
Not only that, but Delphi code can be used in C++ projects. Just add the units to the project, and in your C++ code include the auto-generated unitname.hpp file. You can't (easily) use C++ code from Delphi, but you could create new modules in Delphi and use them from C++. As you do this, more and more of your app will slowly become Delphi code - ie, you don't need to rewrite in a different language all in one go.
As a Delphi developer, I'd suggest going the C++Builder route. Get it working with MFC, and then migrate your windows to the VCL. At that point, you could start rewriting modules in Delphi, or you may find yourself comfortable enough in C++ to continue developing as is.
Edit: I noticed in a reply above you like the idea above of making it a C++ DLL. The link I gave a paragraph or two above of using C++ object from Delphi might be more applicable than I thought. It would fit the RAD Studio (mix of C++ and Delphi) method as well.
Keeping the app as is, tying you to MFC, is likely not very productive - You'll need to learn a GUI toolkit you'll most likely never use for something else (Delphi is great for GUI, MFC doesn't even come close IMO), in addition to a new language.
That leaves you with the choice of rewriting it in a somewhat unfamiliar language using an unfamiliar GUI toolkit, which'll take a lot more time than rewriting it in a familiar language using a familiar GUI toolkit. So you should just get started porting this to Delphi.
Rewriting C++ code in Delphi isn't as easy as you think. A better way to rewrite it is by just redesigning it from scratch, without looking at the old code. Feel free to look how the old application worked, so you can rebuild it. Just don't look at the code. That way, you should get a more modern result.
Of course, if you use the RAD Studio then you have both the C++ as Delphi compiler, thus it should be able to continue to develop the C++ application, although this means you have to learn C++. Then again, any good programmer should be able to just move to another programming language and learn to use it within 2 weeks to a month. C++ can be complex but still, learning C++ and then maintaining the legacy app should take a lot less time than a complete rewrite.
Do keep in mind that any generic C++ application should be able to be compiled for any platform, although the MFC will probably restrict this to just Windows. Still, it's a language that has an even better backwards compatibility than Delphi!
But to keep in mind, will this app run on a different platform in the future? Should it become a .NET application? Or run on Linux? Should it support tablet computers? Android? Your choices today might be outdated again in two years. And since Delphi has a bit uncertain future right now, mostly because C#/.NET became so popular, you might have a more safe bet with C++. Try to replace the MFC libraries with a more modern UI technology, preferably one that's available for multiple platforms, and think very, very well about the future usages of this application.
In general I'd say:
If it's a tiny tool application, and it takes just a couple of days to do a full rewrite: go for it. Don't waste your time creating dll wrappers or to interface with the existing code in other ways. Just do a full rewrite and be done with it.
Otherwise: you'll probably be making changes in one specific area of the application at the time only. Unless the code is a complete spaghetti, you could even get away with making some local changes without fully understanding the implementation details of the rest of the code.
In any case, you need to invest some time into understanding the application and its language + frameworks.
You have a great opportunity to learn C++ and MFC. Take advantage of it. When Delphi goes astray you will have the required knowledge to keep on coding with a language that won't go away so easily, and you can even broaden your development horizons to areas Delphi (and C++ Builder) will never reach. MFC is no more outdated than the VCL is (although I agree the original design is worse).
Good UI programming has nothing to do with the ability to drop controls on a form visually. Many great applications are not built that way. Actually, trying to rewrite it in Delphi could bring you issue in the future, as long as Embarcadero delivers slowly, and without a credible roadmap.
I recommend
1) Keep the app as is and become a C++ MFC developer. But I don't like the idea of using an outdated technology (MFC) for years to come, trying to keep up with new Windows versions and UI standards. It somehow feels like making several steps backwards and I don't think this is the best way to go (?)
Since MFC is well supported and keeps going with the time. MFC is also a what-you'd-call intrusive framework, meaning that the framework dependencies are usually not easily refactored. (The author of CPPDepend published some nice stats on that IIRC, but I can certainly vouch for this from my own experience with large MFC applications).
If you're gonna rewrite to any modern UI framework, don't code the UI in C++ (judging from the fact that Delphi is an option, it is not about realtime visualizations or something like that).
(I'll unask the unasked question here: I you're gonna rewrite, XXXXXXXXXXXXX?) please gentle(wo)men, let's not do the flame
Does the app come with a descent amount of automated tests? If not you're pretty much stuck with option 1 and hope for the best. If there are many tests you can do a lot more with the code without breaking all kinds of things you didn't know were there.
I want to run a Delphi application(With forms vcl, forms, etc) using another application with RemObject Pascal Scripter.
will RemObject Pascal Scripter support all the areas of delphi ,
If so can i include 3rd party VCL
If not what can you recommend me to build interpretable applications with forms and controls
will RemObject Pascal Scripter support all the areas of Delphi
Clearly NO. Haven't used it in a while but "all the areas of delphi" is asking allot. Embarcadero itself isn't setting the bar that high with the "Delphi for Mac". Kylix didn't aim for 100% compatibility either.
can i include 3rd party VCL
Any class can be made available to the scripting engine. But the class itself resides on the compiled Delphi side of things, not on the scripted side.
what can you recommend me to build interpretable applications with forms and controls
Take a look at the "mission statement" for the engine:
"Pascal Script is a widely-used set of components for Delphi that makes it easy to add Pascal-based scripting support to your applications, so that they can extend or control your application with custom scripts"
The author's not positioning it as an scripting engine for application development, but as an engine for extending the functionality of applications. None the less you can probably do a lot with it, it all depends on how you define "interpretable application".
Well, yes and no.
Yes in the sense that you can expose pretty much every aspect of your application to the scripting engine.
No in the sense that "all aspects of Delphi" is too vague a definition to begin with.
I think that what you want is to control, through scripting, some third party control in your form. That is pretty much doable and it can be achieved by using the Unit Importer tool.
Now, there is not much documentation but you can get some useful advice in this SO question.
I have a frame in a Delphi 2007 application that I want to embed on a form in a Delphi 2010 application. I have control over both applications, so the interface between them can be anything both versions support. There will have to be some communication between the two. The two approaches I can think of are using CreateParented and messages, or using an ActiveForm. I don't have any experience with creating ActiveX controls or out of process servers, but I've heard Delphi makes it pretty easy.
Is one method better than the other, either in terms of easy of use or ease of development? Are there other alternatives? Any gotchas I should watch out for?
The ActiveX way seems to be simplest if you want to keep your frame a D2007 one but embed it as an already compiled object in a D2010 application.
Which tool/approach would you suggest to convert of a large 16bit Windows GUI application, written in old Borland Pascal 7 / OWL, to Delphi?
Understanding the pretty heavy differences between OWL and VCL, as well as the differences between the pointer manipulations in 16bit pascal and the state-of-art using of strings and objects in Delphi - are there any ways/tools which could help to avoid almost complete rewrite of the application?
I think you need to determine;
a) how much of the code is to do with business logic, data(base) manipulation and things like proprietary file structures, mathematical processing etc? This is stuff that might lift largely 'as-is' because it's more likely to be written in 'pascal' with much smaller, obvious elements of OWL/BP7. For instance, when I did this with an application I had a series of units that dealt with loading/saving proprietary files, stuff to calculate easter, stuff to do maths on arrays etc - all of this stuff went from BP7 to Delphi (1) with almost no changes.
b) how much of the code is to do with the GUI (and nothing else) - message loop handlers, dialog element constructors, properities of controls etc. This stuff will take a lot of work to port to Delphi and unless you can find someone with a nice line in .RES->.DFM (or similar), I think you'll be looking at building this bit from scratch. No bad thing because if it's a 16bit Windows app then you'll probably want to take the opportunity to at least make it look a bit more 'modern' anyway. I think this will be the most labour-intensive part of the project.
c) how much of the code is using stuff that you know can be done differently in Delphi, but that would work as it stands in pascal right now? This is where #BloodySmartie's point about migrating to an older version of Delphi makes sense to me. You ought to be able to port that project to something like Delphi 5/7 making obvious (and well-understood) changes to things like string manipulation. The more of this stuff that you can leave unported, the better in my view. Get something that runs and that you check basic behaviour with, and then embark on a process of refactoring/refining to make the most of Delphi as and when the resources allow it. You might have (as I did) arrays of pointers in BP7, where each pointer goes to an array of pointers which ultimately lead to an object - this was how we got around memory limitations in the 16bit Windows world. When I first ported my app, these arrays of pointers to arrays of pointers still worked fine in Delphi and I left them alone until I had the time to do something more 'Delphi-like' with the structures.
But before you do all of that - why are you porting the app? If you're porting it because you're about to make a reasonable number of changes to the app's functionality anyway, then it might really be the right time to rewrite the app. As you're rewriting in Delphi, you are still going to be able to use chunks of functions and procedures that are business-rule based anyway, so it's not necessarily a complete and total rewrite from scratch.
I guess there is no tool to support your migration but i'd try to start in an old Delphi Version like 1,2 or 3. This syntax should be much nearer on BP7 than the syntax of newer Delphi Versions.
At this time, you should first try to just bring your app logic to delphi, without any visual stuff. Then use the form designer to rebuild your GUI.
A important point you should pay attention to is that a DOS string is an ASCII-String, while the Delphi strings up to Delphi 2007 are ANSI-encoded. In Delphi 2009, the string keyword describes a unicode string.
Long-long time ago when I swapped OWL to VCL (in C++) it was just easier to write everything from scratch. There might be some code parts that don't deal with user interface and string manipulations, but otherwise it's totaly different.
In fact one of my biggest app is still in OWL, because I just don't bother to rewrite it. As long as it works, let it be.
we also had - and still have - tons of owl-applications.
so we did port the 16bit owl to 32bit owl and are therefor still developing and maintaining our owl-based applications (actually with Delphi 2007 for win32).
you may find this way easier and faster than switch to vcl.
cheers
Andrej
FrameworkPascal.com provides an effective solution with minimal changes to the original windows 3.1 code. We did it for a while but now we provide a rounded solution with 32 bit compatible OWL units. We also provide with it ODBC SQL units, MAC address based security technology and special units CRT like units which can handle code written for DOS text and graphic modes mode, mixed, with and new 32 bit graphics and targeted at Windows 32/64 GUI applications. Legacy code can be which can be compiled with OWL Windows MDI starting with model applications demos which can be quickly modified.
If you had a differential of either venturing into Delphi land or Qt land which would you choose? I know they are not totally comparable. I for one have Windows development experience with Builder C++ (almost Delphi) and MFC (almost Qt), with a bit more time working with Builder C++. Please take out the cross platform ability of Qt in your analysis.
I'm hoping for replies of people who have worked with both and how he or she would compare the framework, environment, etc.?
Thank you in advance for your replies.
If you are talking UI frameworks, then you should be comparing Qt with the VCL, not the IDE (Delphi in this case). I know I'm being a stickler, but Delphi is the IDE, Object-Pascal is the language, and VCL is the graphical framework.
That being said, I don't think there is anything that even comes close to matching the power and simplicity of the VCL. Qt is great, but it is no VCL.
Edit: This answer was written in 2008. It probably is no longer so apt, though probably it is not entirely useless. Take with salt.
I have used both and have ended up going the Qt route. These are the reasons:
Trolltech offer quick and one-to-one support via email
Qt innovates, and introduces powerful new features regularly
The Qt documentation is amazing, and in the rare cases where it isn't, you can read the source code
Having the source code for Qt also allows you to debug inside your base libraries, which has been a life saver for me on many an occasion
The API is very consistent and well designed. We have put new people on the project and within a month they show deep knowledge of the toolkit and can learn new classes very quickly
It has bindings to other languages, eg. Ruby and Python.
C++ is somewhat of a downside, eg. compile times, packaging, and a less integrated IDE. However Qt does make C++ feel more like a higher level language. QStrings take all the pain out of string handling for example. Thus the additional issues with C++ that you would normally face, eg. more buggy code, are less prevalent in my experience when using Qt.
Also, there are more libraries for Delphi than for Qt, but this is mitigated due to the fact you can just use a c or c++ library in a Qt project, and also because Qt is so fully featured you often don't have to look any further.
It would be a strange situation where I would choose Delphi over Qt for a new project.
I would pick Delphi. Of course you ask any pascalholic and he is sure to answer just the same. ;)
Qt again is fine, but the VCL just feels more polished. But then that could be my years of working with it so it just feels right. My experience with Qt was limited to a short lived project that ended up being rewritten in Delphi after it was determined that cross platform was not really needed thanks to the power of GoGlobal which can make any win32 app a web application, and therefore run on any platform.
It really depends on your needs and experience. I have worked with both (though have to say that the last Delphi version I really worked with was Delphi 6, and I'm currently working with Qt 4.4).
The language
C++ pros:
C++ is more "standard", e.g. you will find more code, libraries, examples etc., and you may freely use the STL and boost, while Object Pascal is more of an exotic language
Qt compiles on different platforms and compilers (Kylix is based on Qt, BTW)
Object Pascal pros:
some dynamic properties are build right into the language, no ugly workarounds like the MOC are needed
the compiler is highly optimized for the language and indeed very fast
the language is less complex than C++ and therefore less error prone
The IDE
Qt pros:
Strictly spoken, there is no IDE for Qt besides the Designer, but it integrates nicely into your preferred IDE (at least Visual Studio and Eclipse)
the designer does a better job with layouts than Delphi forms (Note: this is based on
Delphi 6 experience and may not be true with current versions)
Delphi pros:
The IDE is really polished and easy to use now, and it beats Visual Studio clearly IMO (I have no experience with Eclipse)
there is no point 2... but if I had to assign the buzzword "integrated" I would assign it to the Delphi IDE
The framework
I will leave a comparison to others, as I don't know the newest VCL good enough. I have some remarks:
both frameworks cover most of the needed functionality
both have the source code available, which is a must IMO
both have a more or less consistent structure - I prefer Qt, but this depends on your preferences (remark: I would never say that Qt is almost MFC - I have used MFC for a long time, and both Qt and Delphi - and .NET, for that matter - are way better)
the VCL has more DB-oriented functionality, especially the connection with the visual components
Qt has more painting (2D / 3D / OpenGL) oriented functionality
Other reasons that speak for Qt IMO are the very good support and the licensing, but that depends on your needs. There are large communities for both frameworks,
A big difference between Delphi and Qt is the Qt signal/slots system, which makes it really easy to create N-to-N relationship between objects and avoid tight coupling.
I don't think such a thing exists in Delphi (at least there was no such thing when I used to use it).
I just started experimenting with Qt/C++/Qt Creator and I must admit I was surprised that this "little cute bastard" was just below my nose for some many years and I pay attention to it just now.
It (the framework) looks neat, feature-complete (even was stuff that .NET lacks such as inbuld XQuery support).
Seems that most of the Qt applications written are dealing with 2D/3D/Games.
I believe the downsides are only: having to know C++ and the lack of DevExpress goodies like QuantumGrid.
I am seriously considering porting one of my simple applications (a picture viewer like ThumbsView).
And it REALLY runs from same codebase. FOR REAL!
Forget about Kylix, Mono, Lazarus, Free Pascal. This Qt thing beats them all in 10 times.
Qt Creator is far from IDE. But I hope in the future they will add a more powerfull debugger, code insight and refactoring (at least the "Rename" one) and more meaningful compiler errors.
I would seriously recommend to someone without experience in Pascal/C++ to take the Qt learning curve.
I would pick Delphi, but that is probably because I have programmed it before. It seems there are still a number of companies which use it, and almost everyone who has 8+ years expierence has encountered it somewhere. It seems that most programmers can relate to using it or at least learning Pascal. Not to mention the fact that newer languages (C#) are based on it (at least partially).
Pick Delphi if your concern are native Win32 speed, a first class RAD environment and executable size. Pick QT if you need a truly cross-platform framework coupled with a now-flexible licensing policy and don't mind slightly bloated code.
I ported an old Delphi program under QT/C++, and I must say that QT is the framework that comes closest to VCL in terms of ease of use and power (IMHO)
I'd choose delphi. Only because I have more experience with it. I don't think that there is other reasonabl criterias.
Qt is cross-platform, Delphi not much if we count Kylix. Lazarus is cross-platform, but not quite feature-complete yet.