unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls, ExtCtrls;type  TMyShape = class(TShape)  protected    procedure CMMouseenter(var Message: TMessage); message CM_MOUSEENTER;    procedure CMMouseleave(var Message: TMessage); message CM_MOUSELEAVE;  end;  TForm1 = class(TForm)    Panel1: TPanel;    Button1: TButton;    Button2: TButton;    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);const  W = 50;  H = 50;var  shape: TMyShape;begin  shape := TMyShape.Create(Self);  shape.Parent := Panel1;  shape.Width := W;  shape.Height := H;  Randomize;  shape.Left := Random(Panel1.ClientWidth - W);  shape.Top := Random(Panel1.ClientHeight - H);  shape.Brush.Color := Random($FFFFFF);end;procedure TForm1.Button2Click(Sender: TObject);var  i: Integer;begin  if Panel1.ControlCount = 0 then Exit;  Randomize;  i := Random(Panel1.ControlCount - 1);  Panel1.Controls[i].Free;end;{ TMyShape }procedure TMyShape.CMMouseenter(var Message: TMessage);const  s = '当前 %s 的颜色值是: %.6x';var  WCtrl: TWinControl;begin  WCtrl := Parent;  while WCtrl.HasParent do WCtrl := WCtrl.Parent;  if WCtrl is TForm then TForm(WCtrl).Caption := Format(s, [ClassName,Brush.Color]);  inherited;end;procedure TMyShape.CMMouseleave(var Message: TMessage);const  s = 'Form1';var  WCtrl: TWinControl;begin  WCtrl := Parent;  while WCtrl.HasParent do WCtrl := WCtrl.Parent;  if WCtrl is TForm then TForm(WCtrl).Caption := s;  inherited;end;end.

object Form1: TForm1  Left = 0  Top = 0  Caption = 'Form1'  ClientHeight = 212  ClientWidth = 395  Color = clBtnFace  Font.Charset = DEFAULT_CHARSET  Font.Color = clWindowText  Font.Height = -11  Font.Name = 'Tahoma'  Font.Style = []  OldCreateOrder = False  PixelsPerInch = 96  TextHeight = 13  object Panel1: TPanel    Left = 8    Top = 8    Width = 297    Height = 193    Caption = 'Panel1'    TabOrder = 0  end  object Button1: TButton    Left = 311    Top = 40    Width = 75    Height = 25    Caption = #28155#21152    TabOrder = 1    OnClick = Button1Click  end  object Button2: TButton    Left = 311    Top = 85    Width = 75    Height = 25    Caption = #38543#26426#21024#38500    TabOrder = 2    OnClick = Button2Click  endend