有关U盘操作,急!!!(50分)

我做了如下操作为什么没发应????
TForm1.FormCreate(Sender: TObject);
var MMsg: TMessage
begin
Case MMsg.WParam of
32768: //U盘放入
begin
showmessage('U盘放入');
end;
32772: //U盘取出
begin
showmessage('U盘取出');
end;
else DefWindowProc(Handle,MMsg.Msg, MMsg.WParam, MMsg.LParam);
end;
end;

TForm1.FormCreate(Sender: TObject);
你挂接要处理的消息了吗

to Mike1234567890
要怎么样挂接,请赐教

// Component to detect when usb devices are connected or disconnected
// using RegisterDeviceNotification

unit U_Usb;

interface

uses
Windows, Messages, SysUtils, Classes, Forms;

type

PDevBroadcastHdr = ^DEV_BROADCAST_HDR;
DEV_BROADCAST_HDR = packed record
dbch_size: DWORD;
dbch_devicetype: DWORD;
dbch_reserved: DWORD;
end;

PDevBroadcastDeviceInterface = ^DEV_BROADCAST_DEVICEINTERFACE;
DEV_BROADCAST_DEVICEINTERFACE = record
dbcc_size: DWORD;
dbcc_devicetype: DWORD;
dbcc_reserved: DWORD;
dbcc_classguid: TGUID;
dbcc_name: short;
end;

const
GUID_DEVINTERFACE_USB_DEVICE: TGUID = '{A5DCBF10-6530-11D2-901F-00C04FB951ED}';
DBT_DEVICEARRIVAL = $8000; // system detected a new device
DBT_DEVICEREMOVECOMPLETE = $8004; // device is gone
DBT_DEVTYP_DEVICEINTERFACE = $00000005; // device interface class

type

TComponentUSB = class(TComponent)
private
FWindowHandle: HWND;
FOnUSBArrival: TNotifyEvent;
FOnUSBRemove: TNotifyEvent;
procedure WndProc(var Msg: TMessage);
function USBRegister: Boolean;
protected
procedure WMDeviceChange(var Msg: TMessage); dynamic;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property OnUSBArrival: TNotifyEvent read FOnUSBArrival write FOnUSBArrival;
property OnUSBRemove: TNotifyEvent read FOnUSBRemove write FOnUSBRemove;
end;


procedure Register;

implementation

constructor TComponentUSB.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FWindowHandle := AllocateHWnd(WndProc);
USBRegister;
end;

destructor TComponentUSB.Destroy;
begin
DeallocateHWnd(FWindowHandle);
inherited Destroy;
end;

procedure TComponentUSB.WndProc(var Msg: TMessage);
begin
if (Msg.Msg = WM_DEVICECHANGE) then
begin
try
WMDeviceChange(Msg);
except
Application.HandleException(Self);
end;
end
else
Msg.Result := DefWindowProc(FWindowHandle, Msg.Msg, Msg.wParam, Msg.lParam);
end;

procedure TComponentUSB.WMDeviceChange(var Msg: TMessage);
var
devType: Integer;
Datos: PDevBroadcastHdr;
begin
if (Msg.wParam = DBT_DEVICEARRIVAL) or (Msg.wParam = DBT_DEVICEREMOVECOMPLETE) then
begin
Datos := PDevBroadcastHdr(Msg.lParam);
devType := Datos^.dbch_devicetype;
if devType = DBT_DEVTYP_DEVICEINTERFACE then
begin // USB Device
if Msg.wParam = DBT_DEVICEARRIVAL then
begin
if Assigned(FOnUSBArrival) then FOnUSBArrival(Self);
end
else
begin
if Assigned(FOnUSBRemove) then FOnUSBRemove(Self);
end;
end;
end;
end;

function TComponentUSB.USBRegister: Boolean;
var
dbi: DEV_BROADCAST_DEVICEINTERFACE;
Size: Integer;
r: Pointer;
begin
Result := False;
Size := SizeOf(DEV_BROADCAST_DEVICEINTERFACE);
ZeroMemory(@dbi, Size);
dbi.dbcc_size := Size;
dbi.dbcc_devicetype := DBT_DEVTYP_DEVICEINTERFACE;
dbi.dbcc_reserved := 0;
dbi.dbcc_classguid := GUID_DEVINTERFACE_USB_DEVICE;
dbi.dbcc_name := 0;

r := RegisterDeviceNotification(FWindowHandle,
@dbi,
DEVICE_NOTIFY_WINDOW_HANDLE);
if Assigned(r) then Result := True;
end;


procedure Register;
begin
RegisterComponents('GH', [TComponentUSB]);
end;


end.

多人接受答案了。