I've found several snippets and .pas files that can detect when USB flash drives are inserted and removed. Some give all kind of good information, however what I need is the devices' unique serial number, not the volumes' serial number.
My current .pas file (which I don't remember where I found) also seems to detect SD cards (which I like). If you want a look, you can find it here (it only returns the drive number and inserted/removed):
unit UsbDetector;
interface
uses Classes;
type
TUsbDriveChanged = procedure (Sender: TObject; Drive: string; Attached: boolean) of object;
procedure StartUsbDetector(NotifyProc: TUsbDriveChanged);
procedure StopUsbDetector;
implementation
uses Windows, Messages, Forms, SysUtils;
type
TUSBDetector = class(TObject)
private
fUsbDriveChanged: TUsbDriveChanged;
protected
procedure DeviceChanged(Msg: UINT; wParam, lParam: Longint);
procedure DoUsbDriveChanged(Drive: string; Attached: Boolean); dynamic;
public
constructor Create(NotifyProc: TUsbDriveChanged);
destructor Destroy; override;
property OnUsbDriveChanged: TUsbDriveChanged read fUsbDriveChanged;
end;
var mUSBDetector: TUSBDetector;
procedure StartUsbDetector(NotifyProc: TUsbDriveChanged);
begin
if not Assigned(mUsbDetector) then
mUsbDetector := TUsbDetector.Create(NotifyProc);
end;
procedure StopUsbDetector;
begin
FreeAndNil(mUsbDetector);
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
fPrevWndProc: TFNWndProc = nil;
function UsbWndProc(hWnd: HWND; Msg: UINT; wParam, lParam: Longint): Longint; stdcall;
begin
Result := CallWindowProc(fPrevWndProc, hWnd, Msg, wParam, lParam);
if (Msg = WM_DEVICECHANGE) and (mUsbDetector <> nil) then
mUsbDetector.DeviceChanged(Msg, wParam, lParam);
end;
constructor TUSBDetector.Create(NotifyProc: TUsbDriveChanged);
begin
inherited Create;
fUsbDriveChanged := NotifyProc;
if not Assigned(fPrevWndProc) then
begin
fPrevWndProc := TFNWndProc(GetWindowLong(Application.Handle, GWL_WNDPROC));
SetWindowLong(Application.Handle, GWL_WNDPROC, LongInt(@UsbWndProc));
end;
end;
destructor TUSBDetector.Destroy;
begin
//SetWindowLong(Application.Handle, GWL_WNDPROC, LongInt(@fPrevWndProc));
inherited Destroy;
end;
procedure TUSBDetector.DeviceChanged(Msg: UINT; wParam, lParam: LongInt);
var
lpdbhHeader: PDevBroadcastHeader;
lpdbvData: PDevBroadcastVolume;
dwIndex: Integer;
lpszDrive: string;
begin
// Get the device notification header
lpdbhHeader := PDevBroadcastHeader(lParam);
// Handle the message
lpszDrive := '';
case WParam of
DBT_DEVICEARRIVAL: {a USB drive was connected}
begin
if lpdbhHeader^.dbch_devicetype = DBT_DEVTYP_VOLUME then
begin
lpdbvData := PDevBroadcastVolume(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;
DoUsbDriveChanged(lpszDrive, True);
end;
end;
DBT_DEVICEREMOVECOMPLETE: {a USB drive was removed}
begin
if lpdbhHeader^.dbch_devicetype = DBT_DEVTYP_VOLUME then
begin
lpdbvData := PDevBroadcastVolume(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;
DoUsbDriveChanged(lpszDrive, False);
end;
end;
end;
end;
procedure TUSBDetector.DoUsbDriveChanged(Drive: string; Attached: Boolean);
begin
if Assigned(fUsbDriveChanged) then
fUsbDriveChanged(Self, Drive, Attached);
end;
end.
P.S. The code highlight is fail.
All in all; When a removable is inserted/removed, get drive letter and its unique serial number. Maybe combine the already given code with a WMI call "where Index=found_index".
****EDIT!**** I removed the "where" clause in the code given by RRUZ. I finally found out how to handle the arrays, so I use that to find Capabilities[i]=7 to get all removable media. Now I just need to connect this code with the above code. I am thinking using Index, but I don't know how to use GetDrive MapInfo. If you could provide me with an example on getting the drive letter, my question is solved.
You can use the WMI library by Magenta Systems which takes most of the pain of using WMI queries. The free download includes source and an example project that allows you to play with the API and queries to your hearts content. You will want to keep a link to the official Microsoft API documentation which will help you with what query to execute to get what information...your interested in querying the classes using SQL like syntax queries.
For example, executing the query
SELECT * FROM Win32_DiskDrive Where InterfaceType = 'USB'
returns a wealth of information about all of the USB devices currently connected to the machine. You can then use the PNPDeviceID as a unique identifier.
EDIT checking the only USB device I had handy returned a hardware serial number of "u" but a very long and valid looking PNPDeviceID which appeared to include a serial number, which is why I suggested that field.
EDIT You can get the drive letter by performing a query against Win32_LogicalDisk you can also query Win32_DiskDriveToDiskPartition which contains a mapping between Win32_DiskDrive and Win32_DiskPartition. Finally Win32_LogicalDiskToPartition then maps a logical disk to a partition which in turn gives you the ability to link a physical USB drive to a specific drive letter.