[Delphi] Detekcia USB

// 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
  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.

unit Main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, U_Usb;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    procedure MyProc(Sender: TObject);
    { Public declarations }
  end;

var
  Form1: TForm1;
  _USB: TComponentUSB;


implementation

{$R *.dfm}

procedure TForm1.MyProc(Sender: TObject);
begin

  ShowMessage('ok');

end;


procedure TForm1.FormCreate(Sender: TObject);
begin

  _USB:= TComponentUSB.Create(Self);
  _USB.OnUSBArrival:= MyProc;

end;

procedure TForm1.FormDestroy(Sender: TObject);
begin

  _USB.Destroy;

end;

unit Main;

interface

uses
  Windows, Messages, Forms, Classes, Controls, StdCtrls;

type
  TForm1 = class(TForm)
    Label1: TLabel;
  private
    { Private declarations }
  public
    procedure WMDEVICECHANGE(var Msg: TMessage); message WM_DEVICECHANGE;
    { Public declarations }
  end;

//------------------------------------------------------------------------------


// Device constants
const
  DBT_DEVICEARRIVAL          =  $00008000;
  DBT_DEVICEREMOVECOMPLETE   =  $00008004;
  DBT_DEVTYP_VOLUME          =  $00000002;
 
// Device structs
type
  _DEV_BROADCAST_HDR         =  packed record
     dbch_size:              DWORD;
     dbch_devicetype:        DWORD;
     dbch_reserved:          DWORD;
  end;
  DEV_BROADCAST_HDR          =  _DEV_BROADCAST_HDR;
  TDevBroadcastHeader        =  DEV_BROADCAST_HDR;
  PDevBroadcastHeader        =  ^TDevBroadcastHeader;
 
type
  _DEV_BROADCAST_VOLUME      =  packed record
     dbch_size:              DWORD;
     dbch_devicetype:        DWORD;
     dbch_reserved:          DWORD;
     dbcv_unitmask:          DWORD;
     dbcv_flags:             WORD;
  end;
  DEV_BROADCAST_VOLUME       =  _DEV_BROADCAST_VOLUME;
  TDevBroadcastVolume        =  DEV_BROADCAST_VOLUME;
  PDevBroadcastVolume        =  ^TDevBroadcastVolume;


//------------------------------------------------------------------------------

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.WMDEVICECHANGE(var Msg: TMessage);
var  lpdbhHeader:   PDevBroadcastHeader;
     lpdbvData:     PDevBroadcastVolume;
     dwIndex:       Integer;
     lpszDrive:      String;
begin
 
  // Perform inherited
  inherited;
 
  // Get the device notification header
  lpdbhHeader:=PDevBroadcastHeader(Msg.lParam);
 
  // Handle the message
  lpszDrive:='Drive ';
  case Msg.WParam of

     DBT_DEVICEARRIVAL       :    {a USB drive was connected}
     begin
        if (lpdbhHeader^.dbch_devicetype = DBT_DEVTYP_VOLUME) then
        begin
           lpdbvData:=PDevBroadcastVolume(Msg.lParam);
           for dwIndex :=0 to 25 do
           begin
              if ((lpdbvData^.dbcv_unitmask shr dwIndex) = 1) then
              begin
                 lpszDrive:=lpszDrive+Chr(65+dwIndex)+':';
                 break;
              end;
           end;

         Label1.Caption:=lpszDrive + ' connected';
        end;
     end;

     DBT_DEVICEREMOVECOMPLETE:    {a USB drive was removed}
     begin
        if (lpdbhHeader^.dbch_devicetype = DBT_DEVTYP_VOLUME) then
        begin
           lpdbvData:=PDevBroadcastVolume(Msg.lParam);
           for dwIndex:=0 to 25 do
           begin
              if ((lpdbvData^.dbcv_unitmask shr dwIndex) = 1) then
              begin
                 lpszDrive:=lpszDrive+Chr(65+dwIndex)+':';
                 break;
              end;
           end;

        Label1.Caption:=lpszDrive + ' removed';
        end;
     end;
  end;
end;


end.