I am trying to streaming. I spent a lot of time but I didn't find the proper solution.

I have two classes, TClass1, TClass2. Although the parent of AClass2 is AClass1, AClass2 isn't saved into specified file, only AClass1 is.

I want Class1.txt should be like this:

object TClass1
Value1 = 0
object TClass2
Value2 = 0
end

I really appreciate any help you can provide.
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AClass1 is not the parent of AClass2. The two classes have no relationship, certainly not a hierarchical relationship.

You make AClass1 the *owner* (not the *ancestor*) of AClass2 for that single instantiation in your program (i.e. responsible for correctly freeing the instance).

However, TClass1 and TClass2 are completely unrelated, and know nothing about each other's properties.
Perhaps you are looking for something like the attached zipped unit1.pas.

Howard

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Thank you for your respond. I find that my real problem is more complex and need more help from you.

I want my TClass1 can contain many TClass2. It means that number of TClass2 in TClass1 is not fixed.

I've tried to use TComponentList, but it does not work. I knew that TCollection supports streaming, however, TClass1 and TClass2 must be TComponent.

2014-12-15 0:23 GMT+07:00 Howard Page-Clark :

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Try TObjectList.

2014-12-15 1:02 GMT-03:00 Ki?n Nguy?n Ti?n Trung :

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You may have to add
procedure GetChildren(Proc: TGetChildProc; Root: TComponent); override; to TClass1

procedure TClass1.GetChildren(Proc: TGetChildProc; Root: TComponent);
begin
for i = 0 to ListOfClass2.count-1 do
Proc(ListOfClass2[i]);
end;

When loaded you need to put them back into that list. You con override TClass2.Loaded. The Owner of each Class2 will be the Class1 that saved it.

Try TObjectList.

That does not support streaming.

The trick is overriding some TComponent methods.

TClass1
    procedure GetChildren(Proc: TGetChildProc; Root: TComponent); override;
TClass2
    procedure SetParentComponent(Value: TComponent); override;
    function GetParentComponent: TComponent; override;
    function HasParent: Boolean; override;

See for example
lazarus/examples/designnonlcl/mywidgetset.pas
class TMyWidget

Mattias

I got it!

Thank all of you very much.

2014-12-15 17:49 GMT+07:00 Mattias Gaertner :

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