unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls, Generics.Collections;type  TForm1 = class(TForm)    Button1: TButton;    procedure Button1Click(Sender: TObject);  private    procedure KeyNotify(Sender: TObject; const Item: string;      Action: TCollectionNotification);    procedure ValueNotify(Sender: TObject; const Item: Integer;      Action: TCollectionNotification);  end;var  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.KeyNotify(Sender: TObject; const Item: string;  Action: TCollectionNotification);begin  case Action of    cnAdded     : ShowMessageFmt('Key_Add: %s', [Item]);    cnRemoved   : ShowMessageFmt('Key_Remove: %s', [Item]);    cnExtracted : ShowMessageFmt('Key_Extract: %s', [Item]);  end;end;procedure TForm1.ValueNotify(Sender: TObject; const Item: Integer;  Action: TCollectionNotification);begin  case Action of    cnAdded     : ShowMessageFmt('Value_Add: %d', [Item]);    cnRemoved   : ShowMessageFmt('Value_Remove: %d', [Item]);    cnExtracted : ShowMessageFmt('Value_Extract: %d', [Item]);  end;end;  procedure TForm1.Button1Click(Sender: TObject);var  Dictionary: TDictionary
    
     ;begin  Dictionary := TDictionary
     
      .Create();  Dictionary.OnKeyNotify := KeyNotify;  Dictionary.OnValueNotify := ValueNotify;  Dictionary.Add('n1', 111); {Key_Add: n1;  Value_Add: 111}  Dictionary.Add('n2', 222); {Key_Add: n2;  Value_Add: 222}  Dictionary.AddOrSetValue('n1', 123); {Value_Remove: 111;  Value_Add: 123}  Dictionary.Remove('n1');      {Key_Remove: n1;  Value_Remove: 111}  Dictionary.ExtractPair('n2'); {Key_Extract: n2;  Value_Extract: 222}  Dictionary.OnKeyNotify := nil;  Dictionary.OnValueNotify := nil;    Dictionary.Free;end;end.