Отслеживать переход мышки на компонент и уход ее

Code:

unit ImageEx;

interface

uses

  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,

  Dialogs, ExtCtrls;

type

  TImageEx = class (TImage)

  private

    { Private declarations }

    FOnMouseLeave: TNotifyEvent;

    FOnMouseEnter: TNotifyEvent;

    procedure CMMouseEnter(var msg: TMessage);

      message CM_MOUSEENTER;

    procedure CMMouseLeave(var msg: TMessage);

      message CM_MOUSELEAVE;

  protected

    { Protected declarations }

    procedure DoMouseEnter; dynamic;

    procedure DoMouseLeave; dynamic;

  public

    { Public declarations }

  published

    { Published declarations }

    property OnMouseEnter: TNotifyEvent read FOnMouseEnter write FOnMouseEnter;

    property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;

  end;

procedure Register;

implementation

procedure Register;

begin

  RegisterComponents('Additional', [TImageEx]);

end;

{ TImageEx }

procedure TImageEx.CMMouseEnter(var msg: TMessage);

begin

  DoMouseEnter;

end;

procedure TImageEx.CMMouseLeave(var msg: TMessage);

begin

  DoMouseLeave;

end;

procedure TImageEx.DoMouseEnter;

begin

  if Assigned(FOnMouseEnter) then FOnMouseEnter(Self);

end;

procedure TImageEx.DoMouseLeave;

begin

  if Assigned(FOnMouseLeave) then FOnMouseLeave(Self);

end;

end.

Code:

{ You may call this function in a global event procedure,

linking as many components events to it as you need. }

function FindControlAtPos: TWinControl;

var

  Pt: TPoint;

begin

  GetCursorPos(Pt);

  Result := FindControl(WindowFromPoint(Pt));

end;

{ (Beispiel) Hier die allgemein gultige Procedure fur OnMouseUp.

Die Behandlung von OnClick bleibt dabei erhalten:

die Funktionalitat aus OnMouseUp kommt dazu. }

{ (example) There's the global proc for the OnMouseUp event.

Note: OnClick keeps working, so you can "add" the OnMouseUp

facility to no cost. }

procedure TForm1.GenericMouseUp(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

var

  TWC: TWinControl;

begin

  TWC := FindControlAtPos;

  //what for a class !

Showmessage('Here we are: ' + TWC.ClassName);

  //Let it blink...

TWC.Visible := False;

  Sleep(150);

  TWC.Visible := True;

end;