The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

    Mastodon

  • Twitter Updates

  • My Flickr Stream

    20140508-Delphi-2007--Project-Options--Cannot-Edit-Application-Title-HelpFile-Icon-Theming20140430-Fiddler-Filter-Actions-Button-Run-Filterset-now20140424-VMware-Fusion-6.0.3.-no-reclaimable
    More Photos

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,860 other subscribers

Archive for the ‘Stackoverflow’ Category

Next Entries »

Answered @ stackoverflow – on virtual constructors called through class references in Delphi

Posted by jpluimers on 2009/04/27

I just tried to elaborate on an answer to a question from Michael Justin on stackoverflow.
(yes, that’s the author of some message broker clients like the Habari ActiveMQ client that allows Delphi applications to talk to the Apache ActiveMQ message queueing broker).

His question is on virtual constructors and class reference: How can I detect if a Delphi class has a virtual constructor?
The combination of class references and virtual constructors is one of the fundaments of how Delphi became Delphi; in simple terms:

  • class references allow you to register components on the component palette in Delphi
  • virtual constructors allows the designer to construct  the instances of those components at design time

That’s why I think it is important to describe the distinction between virtual constructors and regular non-virtual constructors in the answer below (which is a copy of the answer I posted to stackoverflow)

Read the rest of this entry »

Posted in Delphi, Development, Pingback, Software Development, Stackoverflow | Leave a Comment »

Delphi – bizarre use of class helpers to circumvent ‘with’

Posted by jpluimers on 2009/04/27

Quite a while ago, a co-worker asked how to get tot the Instance variable when using a with statement like this:

function TMyForm.ExecuteForm(FormClass: TFormClass): Integer;
begin
  with FormClass.Create(self) do
    try
      Result := ShowModal;
    finally
      Free;
    end;
end;

So I wrote the blog entry below when I started my blog last week, and set the published date to somewhere early May, a week that will be really busy.
Then I found out about the Stackoverflow question Reference object instance created using “with” in Delphi followed by the answer by user ‘Alexander‘ (a really smart Russian guy).
Enough coincidence to publish the blog article earlier than scheduled :-) 

Before I explain why I really hate ‘with’, lets show what my co-worker wanted, and my solution: Read the rest of this entry »

Posted in Delphi, Development, Pingback, Software Development, Stackoverflow | 2 Comments »

Next Entries »