USB 设备的插入和拔出

rundll32.exe hotplug.dll,HotPlugEjectVetoed \\.\pipe\PNP_HotPlug_Pipe_0.{00FE6FE2-E156-4DB4-8456-96DDC61D33F6}

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http://www.swissdelphicenter.ch/torry/showcode.php?id=2211

...detect if a USB device is connected or disconnected?

Author: Miguel Lucero  

Homepage: www.lsis.com.ar

// 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;

implementation

constructor TComponentUSB.Create(AOwner: TComponent);

begin

 inherited Create(AOwner);

 FWindowHandle := AllocateHWnd(WndProc);

 USBRegister;

end;

destructor TComponentUSB.Destroy;

begin

UnregisterDeviceNotification(FWindowHanlde);

 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;

end.