How it works...

Selecting one or more styles from Project | Options | Application | Appearance will cause the Delphi linker to link the style resource into your executable. It is possible to link many styles into your executable, but you can use only one style at a time. So, how does Delphi know which style you want to use when there are more than one? If you check the Project file (the file with the .dpr extension) by going to Project | View Source Menu (for shortcut lovers, Ctrl + V with the project selected in Project Manager), you can see where and how this little bit of magic happens.

The following lines are the interesting section:

begin 
  Application.Initialize; 
  Application.MainFormOnTaskbar := True; 
  TStyleManager.TrySetStyle('Iceberg Classico'); 
  Application.CreateForm(TMainForm, MainForm); 
  Application.Run; 
end

When we selected the Iceberg Classico style as the default style, the Delphi IDE added a line just before the creation of the main form, setting the default style for all the applications using TStyleManager.TrySetStyle static methods.

TStyleManager is a very important class when you deal with VCL styles. We'll see more about it in an upcoming recipe, where you'll learn how to change styles at runtime.