unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
  Windows;

type

  { TForm1 }

  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  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
  DBT_DEVTYP_VOLUME = $00000002;


var
  Form1: TForm1;

implementation

uses JwaWinUser, JwaDbt;

{$R *.lfm}

type
  TMWndProc = Windows.WNDPROC;

var
   OldWndProc: TMWndProc;

function MyWndProc(my_wnd : HWND; Msg : UINT; my_wparam : WPARAM; my_lparam : LPARAM): LRESULT; stdcall;
var
  devType : Integer;
  Datos : PDevBroadcastHdr;
begin
  Result := 0;
  case Msg of
    WM_DEVICECHANGE:
    begin
      if (my_wparam = DBT_DEVICEARRIVAL) or (my_wparam = DBT_DEVICEREMOVECOMPLETE) then
      begin
        Datos := PDevBroadcastHdr(Pointer(my_lparam));
        devType := Datos^.dbch_devicetype;

        if devType = DBT_DEVTYP_VOLUME then
        begin
           if my_wparam = DBT_DEVICEARRIVAL then
             ShowMessage('USB-Gerät eingesteckt!')
           else
             ShowMessage('USB-Gerät herausgenommen!');
        end;
      end;

      // Return TRUE to grant the request
      // Return BROADCAST_QUERY_DENY to deny the request.

      // Weiß nicht genau was ich hier zurück geben soll

    end; // WM_DEVICECHANGE
  end; // case

  Result := Windows.CallWindowProc(OldWndProc, my_wnd, Msg, my_wparam, my_lparam);
end;

{ TForm1 }

procedure TForm1.FormCreate(Sender: TObject);
var
  dbi: DEV_BROADCAST_DEVICEINTERFACE_W;
  dbv: DEV_BROADCAST_VOLUME;
  Size: Integer;
  RDN: HDEVNOTIFY;
  arr : array[0 .. 0] of word;
begin
  arr[0] := 0;
  Size := SizeOf(DEV_BROADCAST_DEVICEINTERFACE_W);
  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 := arr;
  RDN := RegisterDeviceNotificationW(Form1.Handle, @dbi, DEVICE_NOTIFY_WINDOW_HANDLE);
  if not Assigned(RDN) then
    ShowMessage('Error Register Message');

  Size := SizeOf(DEV_BROADCAST_VOLUME);
  ZeroMemory(@dbv, Size);
  dbv.dbcv_size := Size;
  dbv.dbcv_devicetype := DBT_DEVTYP_VOLUME;
  dbv.dbcv_reserved := 0;
  dbv.dbcv_flags := 0;
  RDN := RegisterDeviceNotification(Form1.Handle, @dbi, DEVICE_NOTIFY_WINDOW_HANDLE);
  if not Assigned(RDN) then
    ShowMessage('Error Register Message');

  OldWndProc := TMWndProc(Windows.GetWindowLong(Self.Handle, GWL_WNDPROC));
  Windows.SetWindowLong(Self.Handle, GWL_WNDPROC, LongInt(@MyWndProc));
end;


end.