From 30f514eb6bf1ef0acf5fd6f7fa0246671f5089fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C3=ABl=20Van=20Canneyt?= <michael@freepascal.org>
Date: Mon, 19 Feb 2024 11:21:34 +0100
Subject: [PATCH] * Add CanObserve and ObserverAdded to TComponent, for delphi
 compatibility

---
 rtl/objpas/classes/classesh.inc |  2 ++
 rtl/objpas/classes/compon.inc   | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/rtl/objpas/classes/classesh.inc b/rtl/objpas/classes/classesh.inc
index ca3bbf8c0a..91136c9bcd 100644
--- a/rtl/objpas/classes/classesh.inc
+++ b/rtl/objpas/classes/classesh.inc
@@ -2434,6 +2434,8 @@ type
   protected
     FComponentStyle: TComponentStyle;
     function GetObservers: TObservers;virtual;
+    function CanObserve(const ID: Integer): Boolean; virtual;
+    procedure ObserverAdded(const ID: Integer; const Observer: IObserver); virtual;
     procedure GetDeltaStreams(aProc: TGetStreamProc); virtual;
     procedure ReadDeltaStream(const S: TStream);
     procedure ReadDeltaState; virtual;
diff --git a/rtl/objpas/classes/compon.inc b/rtl/objpas/classes/compon.inc
index b3b8394a2f..a495a57997 100644
--- a/rtl/objpas/classes/compon.inc
+++ b/rtl/objpas/classes/compon.inc
@@ -108,10 +108,23 @@ end;
 function TComponent.GetObservers: TObservers;
 begin
   if FDObservers=Nil then
+    begin
     FDObservers:=TObservers.Create;
+    FDObservers.OnCanObserve:=@CanObserve;
+    FDObservers.OnObserverAdded:=@ObserverAdded;
+    end;
   Result:=FDObservers;
 end;
 
+function TComponent.CanObserve(const ID: Integer): Boolean; 
+begin
+  Result:=False;
+end;
+
+procedure TComponent.ObserverAdded(const ID: Integer; const Observer: IObserver); 
+begin
+  // Do nothing, can be used in descendants
+end;
 
 Procedure TComponent.Insert(AComponent: TComponent);