Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>You can use the <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/aa363431%28v=vs.85%29.aspx" rel="noreferrer"><code>RegisterDeviceNotification</code></a> WinAPI function passing the <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/aa363244%28v=vs.85%29.aspx" rel="noreferrer"><code>DEV_BROADCAST_DEVICEINTERFACE</code></a> structure with the <a href="http://msdn.microsoft.com/en-us/library/windows/hardware/ff545821%28v=vs.85%29.aspx" rel="noreferrer"><code>GUID_DEVINTERFACE_COMPORT</code></a> device interface class.</p> <p>Try this sample.</p> <pre><code>type PDevBroadcastHdr = ^DEV_BROADCAST_HDR; DEV_BROADCAST_HDR = packed record dbch_size: DWORD; dbch_devicetype: DWORD; dbch_reserved: DWORD; end; TDevBroadcastHdr = DEV_BROADCAST_HDR; type PDevBroadcastDeviceInterface = ^DEV_BROADCAST_DEVICEINTERFACE; DEV_BROADCAST_DEVICEINTERFACE = record dbcc_size: DWORD; dbcc_devicetype: DWORD; dbcc_reserved: DWORD; dbcc_classguid: TGUID; dbcc_name: Char; end; TDevBroadcastDeviceInterface = DEV_BROADCAST_DEVICEINTERFACE; const DBT_DEVICEARRIVAL = $8000; DBT_DEVICEREMOVECOMPLETE = $8004; DBT_DEVTYP_DEVICEINTERFACE = $00000005; type TDeviceNotifyProc = procedure(Sender: TObject; const DeviceName: String) of Object; TDeviceNotifier = class private hRecipient: HWND; FNotificationHandle: Pointer; FDeviceArrival: TDeviceNotifyProc; FDeviceRemoval: TDeviceNotifyProc; procedure WndProc(var Msg: TMessage); public constructor Create(GUID_DEVINTERFACE : TGUID); property OnDeviceArrival: TDeviceNotifyProc read FDeviceArrival write FDeviceArrival; property OnDeviceRemoval: TDeviceNotifyProc read FDeviceRemoval write FDeviceRemoval; destructor Destroy; override; end; type TForm17 = class(TForm) procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); private { Private declarations } DeviceNotifier : TDeviceNotifier; public { Public declarations } procedure arrival(Sender: TObject; const DeviceName: String); end; var Form17: TForm17; implementation {$R *.dfm} constructor TDeviceNotifier.Create(GUID_DEVINTERFACE : TGUID); var NotificationFilter: TDevBroadcastDeviceInterface; begin inherited Create; hRecipient := AllocateHWnd(WndProc); ZeroMemory(@NotificationFilter, SizeOf(NotificationFilter)); NotificationFilter.dbcc_size := SizeOf(NotificationFilter); NotificationFilter.dbcc_devicetype := DBT_DEVTYP_DEVICEINTERFACE; NotificationFilter.dbcc_classguid := GUID_DEVINTERFACE; //register the device class to monitor FNotificationHandle := RegisterDeviceNotification(hRecipient, @NotificationFilter, DEVICE_NOTIFY_WINDOW_HANDLE); end; procedure TDeviceNotifier.WndProc(var Msg: TMessage); var Dbi: PDevBroadcastDeviceInterface; begin with Msg do if (Msg = WM_DEVICECHANGE) and ((WParam = DBT_DEVICEARRIVAL) or (WParam = DBT_DEVICEREMOVECOMPLETE)) then try Dbi := PDevBroadcastDeviceInterface(LParam); if Dbi.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE then begin if WParam = DBT_DEVICEARRIVAL then begin if Assigned(FDeviceArrival) then FDeviceArrival(Self, PChar(@Dbi.dbcc_name)); end else if WParam = DBT_DEVICEREMOVECOMPLETE then begin if Assigned(FDeviceRemoval) then FDeviceRemoval(Self, PChar(@Dbi.dbcc_name)); end; end; except Result := DefWindowProc(hRecipient, Msg, WParam, LParam); end else Result := DefWindowProc(hRecipient, Msg, WParam, LParam); end; destructor TDeviceNotifier.Destroy; begin UnregisterDeviceNotification(FNotificationHandle); DeallocateHWnd(hRecipient); inherited; end; procedure TForm17.arrival(Sender: TObject; const DeviceName: String); begin ShowMessage(DeviceName); end; procedure TForm17.FormCreate(Sender: TObject); const GUID_DEVINTERFACE_COMPORT : TGUID = '{86E0D1E0-8089-11D0-9CE4-08003E301F73}'; begin DeviceNotifier:=TDeviceNotifier.Create(GUID_DEVINTERFACE_COMPORT); DeviceNotifier.FDeviceArrival:=arrival; end; procedure TForm17.FormDestroy(Sender: TObject); begin DeviceNotifier.Free; end; end. </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow to detect addition of new serial port?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USRRUZ
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow to detect addition of new serial port?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COWew, thanks a lot! I added a form to my current application with the code you provided. When changing the com port WndProc is called but not arrival. A close inspection of `Msg` shows that its `Msg` is indeed `WM_DEVICECHANGE. WParam` is 7, not `DBT_DEVICEARRIVAL` (all other are 0). Changing the condition such that it is executed when `WParam` is 7, `Dbi := PDevBroadcastDeviceInterface (LParam);` returns `nil`, I should have know because `LParam` = 0. `WndProc` is only called once when changing the com port. Any ideas?
      singulars
      1. PO
      1. USArnold
    2. CO@Arnold, what kind of serial port are you adding? because I tried using a [USB serial port adapter](http://www.amazon.com/Belkin-SERIAL-PORT-ADAPTER-F5U409-CU/dp/B00009L7MI) and adding [virtual serial ports](http://www.mks.zp.ua/products/vspdxp/) and in both cases the code works fine (Windows 7 x64).
      singulars
      1. PO
      1. USRRUZ
    3. COI add a USB cable which is (also) seen as a serial port by the ComPortDriver.
      singulars
      1. PO
      1. USArnold
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload