Can I set a property within a TFrame for all instances of the frame at run time?

[XylemFlow 6]

I have created a TFrame at design time using the form designer. I then create several instances of the frame at run time. Is there a way to set a property of the underlying TFrame for all instances at once instead of having to iterate over all instances? For example, when a user changes the language at run time the captions and hints of the buttons in the TFrame need to be updated for all instances.

Edited October 23, 2023 by XylemFlow

[M.Joos 29]

I don't think there is an easy solution. If you really wanna go that route, you would need to intercept the instance creation process by e.g. overwriting the NewInstance method of your FrameXY class. Within that you could then add each created instance into a class var array or a class var TList. You could then e.g add a class procedure "SetLanguage" to your class from within you could iterate over all your instances and delegate this call to a regular instance method.

[Uwe Raabe 1890]

Another approach would be to declare a TMessage descendant that the frame (and probably also any form) subscribes to during creation and unsubscribes from on destruction. Then you can broadcast this message when the language changes.

uses
  System.Messaging;
  
type
  TLanguageMessage = class(TMessage<string>);

...

procedure TMyFrame.HandleLanguageMessage(const Sender: TObject; const M: TMessage);
begin
  var msg := M as TLanguageMessage;
  SwitchToLanguage(M.Value);
end;

... TMyFrame.Create
  FLanguageMessageID := TMessageManager.DefaultManager.SubscribeToMessage(TLanguageMessage, HandleLanguageMessage);
  
... TMyFrame.Destroy
  TMessageManager.DefaultManager.Unsubscribe(TLanguageMessage, FLanguageMessageID, True);
  
... NotifyLanguage
  TMessageManager.DefaultManager.SendMessage(nil, TLanguageMessage.Create('DE'));