怎样截获开关光驱的系统消息

[ltolll]

不是控制光驱开关,只要截获开关光驱的系统消息,其中包括软开关和硬开关(都要能截获)。

[风轻狂]

// 以下来自delphi猛料
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
procedure WMDEVICECHANGE(var msgx: Tmessage); message WM_DEVICECHANGE;
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}

procedure Tform1.WMDEVICECHANGE(var msgx: Tmessage);
const
DBT_DEVICEARRIVAL = $8000;
DBT_DEVICEREMOVECOMPLETE = $8004;
begin
inherited;
case msgx.WParam of
DBT_DEVICEARRIVAL:
Caption := '有了！';
DBT_DEVICEREMOVECOMPLETE:
Caption := '取走了';
end;
end;

end.

[lyl910]

然后怎么用阿，我是初学者，望再指点一下，谢谢！