Hello everyone!
I'm new to FPC/Lazarus, and I would like to thank everyone involved for the
great work. I have maybe a stupid question: I am trying to understand how
Lazarus applies FORMDATA resources to forms. Specifically, in the standard main
unit situation like this:
------- unit1.pas-------
unit Unit1;
type
TForm1 = class(TForm)
Button1: TButton;
end;
var
Form1: TForm1;
------ unit1.lfm -------
object Form1: TForm1
Left = 383
Height = 300
Top = 175
Width = 400
Caption = 'Form1'
ClientHeight = 300
ClientWidth = 400
LCLVersion = '0.9.26.2'
object Button1: TButton
Left = 151
Height = 25
Top = 137
Width = 75
Caption = 'Button1'
TabOrder = 0
end
end
-------
I consider unit.lrs to be simply a translation of unit1.lfm (right?).
Now, unit1.lrs seems to be applied in a way that the newly created TForm1 is
assigned to Unit1.Form1, and the newly created TButton is both a child of
Unit1.Form1 and assigned to Unit1.Form1.Button1 (right?)
I want to have a similar behavior for custom components (data keepers etc.)
with or without Lazarus (I also have to do command-line tools and would like to
move away from C). Like
------- myunit.pas -------
type
TMyComponent = class(TComponent)
FChild : TSomeComponent;
procedure DoSomething;
end;
var
MyComponent : TMyComponent;
implementation
procedure TMyComponent.DoSomething;
begin
// Do something with FChild
end;
------- myunit.lfm -------
object MyComponent: TMyComponent
object FChild : TSomeComponent
SomeProperty : 42
end
end
-------
However, when I use ReadComponentFromBinaryStream() or similar methods to
stream properties and assign the new component (manually) to
MyUnit.MyComponent, I get a TSomeComponend named FChild which is a child of
MyComponent, but it is not assigned to MyUnit.MyComponent.FChild. If I call
MyComponent.DoSomething, FChild is nil. This is not what I want.
Of course, I could iterate through the freshly created components after doing
ReadComponentFromBinaryStream() and use RTTI for TMyComponent (and its field
components) to fix references (I could do that, right?), but isn't it possible
to use existing code for that? As far as I understand the RTL docs,
FixupReferences() etc. have nothing to do with that (right?). So, if the code
which I'm looking for exists (or the functionality is documented somewhere),
where is the code/the documentation (even Delphi docs, if the implementations
in Lazarus and Delphi are similar)?
Maybe related: Function pointers are always unassigned after streaming when
using functions like ReadComponentFrom...(), even if i use
WriteComponentTo...() (with assigned function pointers) first and then just
re-read the stream. Why is that?
I hope this describes the problem/question correctly and I haven't overlooked
any existing docs/discussions.
Thanks again.
ML
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