如何为组件设计响应事情？？

Question

设计的一个图形组件需要当鼠标离开组件的时候响应一个外部事件，应该如何实现？

Answer 1

从TControl继承下来的类有CM_MOUSEENTER和CM_MOUSELEAVE消息即是对应于进入到离开的时候。blog.csdn.net/linzhengqun

Answer 2

http://cache.baidu.com/c?word=delphi%2Cvar%2Ccm%3B%5F%3Bmouseleave%2Cmessage&url=http%3A//www%2Eevget%2Ecom/articles/evget%5F399%2Ehtml&b=0&a=90&user=baidu给控件加入声明：
FOnMouseLeave: TNotifyEvent;
procedure CMMouseLeave(var Msg:TMessage);message CM_MouseLeave;
property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;实现procedure TCustomLabel.CMMouseLeave(var Message: TMessage);
begin
  inherited;
  if Assigned(FOnMouseLeave) then
    FOnMouseLeave(Self);
end;

Answer 3

有楼上的高手为你指点，错不了。
aiirii(ari-淘金坑) 曾帮过我好多次。

Answer 4

//鼠标移动到 Image ,实现抖动效果
//yeeyeeunit MyImage;interfaceuses
  SysUtils, StdCtrls, Classes, Controls, ExtCtrls, Messages, Graphics;const cnstLEFTSTEP=4;
const cnstTOPSTEP=3;type
  TMyImage = class(TImage)
  private
    { Private declarations }
    FMoved:boolean;
    FLabel:TLabel;
    FOnMouseLeave: TNotifyEvent;
    FOnMouseEnter: TNotifyEvent;
    procedure SetMoved(const AValue:boolean);
    procedure SetLabel(AValue:TLabel);    procedure LabelMouseEnter(Sender: TObject);
    procedure LabelMouseLeave(Sender: TObject);
  protected
    { Protected declarations }
    procedure CMMouseEnter(var Message: TMessage); message CM_MOUSEENTER;
    procedure CMMouseLeave(var Message: TMessage); message CM_MOUSELEAVE;
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
  published
    { Published declarations }
    property YMoved: boolean read FMoved write SetMoved;
    property YLabel: TLabel read FLabel write SetLabel;
    property OnMouseEnter: TNotifyEvent read FOnMouseEnter write FOnMouseEnter;
    property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
  end;//procedure Register;implementation
{
procedure Register;
begin
  RegisterComponents('Yeeyee', [TMyImage]);
end;
}
constructor TMyImage.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FMoved:=False;
end;procedure TMyImage.SetMoved(const AValue:boolean);
begin
  if FMoved<>AValue then
  begin
    FMoved:=AValue;
  end;
end;procedure TMyImage.SetLabel(AValue:TLabel);
begin
  if FLabel<>AValue then
  begin
    FLabel:=AValue;
    if Assigned(FLabel) then
    begin
      FLabel.Left:=Left+(Width-FLabel.Width) div 2;
      //FLabel.Top:=Top+Height-FLabel.Height;
      FLabel.Top:=Top+Height+FLabel.Height;
      FLabel.Font.Name:='宋体';
      FLabel.Font.Size:=10;
      FLabel.OnMouseEnter:=LabelMouseEnter;
      FLabel.OnMouseLeave:=LabelMouseLeave;
    end;
  end;
end;procedure TMyImage.LabelMouseEnter(Sender: TObject);
begin
  if Assigned(FLabel) then
  begin
    FLabel.Font.Color:=clBlue;
    FLabel.Cursor:=crHandPoint;    if FMoved then
    begin
      Left:=Left-cnstLEFTSTEP;
      Top:=Top-cnstTOPSTEP;
      FLabel.Left:=FLabel.Left-cnstLEFTSTEP;
      FLabel.Top:=FLabel.Top-cnstTOPSTEP;
    end;
  end;
end;procedure TMyImage.LabelMouseLeave(Sender: TObject);
begin
  if Assigned(FLabel) then
  begin
    FLabel.Font.Color:=clBlue;
    FLabel.Cursor:=crHandPoint;    if FMoved then
    begin
      Left:=Left+cnstLEFTSTEP;
      Top:=Top+cnstTOPSTEP;
      FLabel.Left:=FLabel.Left+cnstLEFTSTEP;
      FLabel.Top:=FLabel.Top+cnstTOPSTEP;
    end;
  end;
end;procedure TMyImage.CMMouseEnter(var Message: TMessage);
begin
  inherited;
  if FMoved then
  begin
    Left:=Left-cnstLEFTSTEP;
    Top:=Top-cnstTOPSTEP;
    FLabel.Left:=FLabel.Left-cnstLEFTSTEP;
    FLabel.Top:=FLabel.Top-cnstTOPSTEP;
  end;
  if Assigned(FLabel) then
  begin
    FLabel.Font.Color:=clBlue;
    FLabel.Cursor:=crHandPoint;
  end;
  Cursor:=crHandPoint;
  if Assigned(FOnMouseEnter) then
    FOnMouseEnter(Self);
end;procedure TMyImage.CMMouseLeave(var Message: TMessage);
begin
  inherited;
  if FMoved then
  begin
    Left:=Left+cnstLEFTSTEP;
    Top:=Top+cnstTOPSTEP;
    FLabel.Left:=FLabel.Left+cnstLEFTSTEP;
    FLabel.Top:=FLabel.Top+cnstTOPSTEP;
  end;    
  if Assigned(FLabel) then
  begin
    FLabel.Font.Color:=clWindowText;
    FLabel.Cursor:=crDefault;
  end;
  Cursor:=crDefault;
  if Assigned(FOnMouseLeave) then
    FOnMouseLeave(Self);
end;end.

Answer 5

（aiirii(ari-淘金坑) 这个方法真不错，谢谢！
以后还请各位多多关照。