unit SomeComponent;

interface

uses
 Controls, Classes, Graphics;

type
 TSomeClass = class(TPersistent)
 private
   FSomeString: String;
   FSomeInteger: Integer;
 public
   constructor Create;
   procedure Assign(Source: TPersistent); override;
 published
   property SomeString: String read FSomeString write FSomeString;
   property SomeInteger: Integer read FSomeInteger write FSomeInteger;
 end;

type
 TSomeComponent = class(TComponent)
 private
   FFont: TFont;
   FSomeClass: TSomeClass;
   procedure SetFont(const AFont: TFont);
   procedure SetSomeClass(const ASomeClass: TSomeClass);
 public
   constructor Create(AOwner: TComponent); override;
   destructor Destroy; override;
 published
   property Font: TFont read FFont write SetFont;
   property SomeClass: TSomeClass read FSomeClass write SetSomeClass;
 end;

procedure Register;

implementation

procedure Register;
begin
 RegisterComponents('My components', [TSomeComponent]);
end;

{ TSomeClass }

procedure TSomeClass.Assign(Source: TPersistent);
begin
 if Source is TSomeClass then
   begin
     FSomeString:=TSomeClass(Source).FSomeString;
     FSomeInteger:=TSomeClass(Source).FSomeInteger;
   end;
end;

constructor TSomeClass.Create;
begin
 FSomeString:='SomeString';
 FSomeInteger:=0;
end;

{ TSomeComponent }

constructor TSomeComponent.Create(AOwner: TComponent);
begin
 inherited Create(AOwner);
 FSomeClass.Create;
 FFont:=TFont.Create;
end;

destructor TSomeComponent.Destroy;
begin
 FSomeClass.Free;
 FFont.Free;
 inherited;
end;

procedure TSomeComponent.SetFont(const AFont: TFont);
begin
 FFont.Assign(AFont);
end;

procedure TSomeComponent.SetSomeClass(const ASomeClass: TSomeClass);
begin
  FSomeClass.Assign(ASomeClass);
end;

end.

constructor TSomeComponent.Create(AOwner: TComponent);
begin
 inherited Create(AOwner);
 FSomeClass:=TSomeClass.Create;
 FFont:=TFont.Create;
end;

procedure TControl.AssignTo(Dest: TPersistent);
begin
 if Dest is TCustomAction then
   with TCustomAction(Dest) do
   begin
     Enabled := Self.Enabled;
     Hint := Self.Hint;
     Caption := Self.Caption;
     Visible := Self.Visible;
     OnExecute := Self.OnClick;
   end
 else inherited AssignTo(Dest);
end;