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Thoughts from David Cornelius

Software development tools and techniques explored--mostly Delphi

Preventing Multiple Application Instances in Delphi with TMutex

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Having worked in Delphi for many years, I've seen the development tool and it's RTL evolve significantly, yet remain resilient in backwards compatibility. Early on, to prevent your application from running multiple times, there were generally two different approaches:

  1. Search for the name of your app's main form by name, or
  2. Search for a "mutex" created by your app.

 

Linux, Lazarus, and Lots of scripting

A friend of mine runs a business selling a Windows application for a niche market. Of course he has a web site with lots of information and a way to download a trial of his software and then pay and register it. Since he's a technical person, likes writing code, likes to keep overhead low, and his needs are fairly simple, he wrote the registration program himself. He's most fluent in Delphi so it was natural to write the registration program in Delphi--an old, but very functional Delphi 2007.

How to Break Delphi's Object Repository

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I'm a long time Delphi user and have taken advantage of the Object Repository quite a bit. It's really handy to take a unit or project that might be useful somewhere else but in a slightly different form and add it to the repository. Later, when you need to use that bit of code, you can select it from the repository right from within Delphi and it will make a copy of that code in your new project.

Diving into .NET

I recently watched most of a dotnetConf, a virtual conference on .NET hosted by Microsoft. All the sessions were recorded and there's a lot of good and relevant content.

I was programming Win32 apps in Delphi while listening and I felt myself yearning for the cool technologies they were discussing. Yeah, Delphi has grown up a bit, but it's no longer the leader, it's following and getting further and further behind the rest of the development community.

The Broader Picture

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When I was in college heading for a degree in Computer Science, I wondered why I needed History or Psychology or English or Art. Hadn't I had enough of that in high school? Why couldn't I just take fun stuff like Assembly Language or Advanced Data Structures? My parents tried to tell me about well-rounded education, how important professional communication is, and the benefits of knowing about the world around me, but it was hard for me to put much more than the minimal effort required to get the grades in those "non-essential" classes.

Delphi Developer Dilemma

I've used Pascal-based compilers for a long time. Similar to many others like me, I started with Turbo Pascal 3 in the 80s, embraced object-oriented extensions in Borland Pascal, attempted to understand OWL but quickly moved to Delphi when it was released, and now churn out blazing database applications on the latest Windows operating systems using internet technologies, advanced reporting tools, and multiple third-party component sets. Sure, I've dabbled in other languages such as C/C++, Visual Basic, .NET with C#, and some scripting languages, but Delphi has been the bulk of my experience for the past 17 years or so.

Simple PHP Web App in HTML5 Builder

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The first application I'll create will be similar to sample ones I had tried in RadPHP. They were simple PHP tutorials and they worked--somewhat. I had some issues, but don't remember whether it was getting all the right libraries in the right place or whether it worked from some locations or browsers or what. In any case, I'm hoping HTML5 Builder will make the process a little smoother.

Installing HTML5 Builder

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It's been a year since my last blog entry and while I've been busy writing Windows applications with Delphi, I've kept an eye on web technologies. I've done some PHP in the past and had purchased RadPHP XE but didn't upgrade to the XE2 version because there were practically no new features and the documentation, which was pitiful, was not improved one bit--in fact it was still labeled XE!

Web Service Timeouts

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While working on a project accessing a slow web service, I found myself needing to extend the timeout of the HTTPRIO component. The web service, when executed straight from a browser, would happily take as long as it needed to before successfully completing. But my Delphi application was timing out.

Mega Update - Part 2

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In the last entry, I gave an overview of the large software update I delivered to a client, an update that should've been done incrementally over a period of several months. From database schema changes, to swapping out a reporting engine, to switching from ANSI to Unicode, I really bit off more than I could chew at once. But it's now working well and I'm once again sleeping at night!

This portion of the story deals with the database changes that were made, both the structure and the character set.

Mega Update - Part 1

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I recently gave a client a major update to their custom application. Actually, "major" doesn't even do it justice. It was more like "mega major" and I don't think I'll take the approach I did ever again. But I wanted to move their code to the latest compilers and to support the latest operating systems. I also needed to change some low-level database constructs. Why all this? Because I'm a best-practices sort of guy.

Widths and Themes

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In the old DOS days, things were simple. You had 25 rows and 80 columns of text. Period. Well, if you knew the right tricks, you could double the rows or columns, but still it was pretty limited. This made programming fairly easy--you knew how much space you had to deal with. With a GUI, or Graphical User Interface, things can get stretched out, you can have larger fonts, and you can have themes on or off. So knowing how much space you have to display stuff isn't quite as cut and dried. But I'm going to look at just one aspect that can be surprising: themes.

DateTimePicker Vista Theme!

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Adding theme support to your application can give your program a whole new look (if you use standard Windows controls) without changing anything else. This works because the controls will actually use a different set of DLLs behind the scene. In Delphi 2007, this is accomplished with a simple checkbox in the project options. (Visit the Delphi Wikia page and search for "Adding Theme Support" for more information.) The DateTimePicker is one of these and I just discovered its new capabilities when themed on Vista or Windows 7.

Starting with Delphi Prism

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I've recently acquired the latest Pascal language compiler from RemObjects, Oxygene. Embarcadero, now the owners of Delphi, decided not to continue development of Delphi for .NET, but instead license this compiler plug-in for Visual Studio from RemObjects. So if you get RAD Studio 2009 from Embarcedero, which includes Delphi 2009 for Win32, you also get a special single-language version of Microsoft Visual Studio with the Pascal compiler from RemObjects.

Delphi History

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Delphi is one of the greatest development environments every produced for Windows. It has an easy to learn, yet strict language that leads to less confusion than C++ and better coding practices than Visual BASIC. Unfortunately, it has been marketed by a company that has made so many changes in direction and name that people have laughed it off. One more change has happened recently, here is the story, which actually starts over 25 years ago, before Windows.
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