如何检测 WiFi 何时(重新)连接?

How to detect when WiFi (re)connects?

抱歉,我没有任何代码可以显示。这可能会使这个问题成为 Programmers 的候选问题,但他们这里没有语言特定区域,我正在寻找 Delphi 解决方案,所以我会在这里问。我希望这是可以接受的。

基本上,我想在 WiFi 连接时自动启动我的 VPN。我将如何检测到它? Google,看来,在这件事上不是我的朋友。

所需的 WinApi 调用未在 Delphi 中实现 - 您必须自己定义和调用它们。在这种情况下,相关功能是:


WlanOpenHandle (MSDN)

WlanRegisterNotification (MSDN)

WLAN_NOTIFICATION_SOURCE structure (MSDN)


您可以将它们定义为:

const
  wlanapi = 'wlanapi.dll';
  WLAN_NOTIFICATION_SOURCE_ACM = [=10=]000008;

type
  GUID = TGUID;
  HANDLE = THandle;

  PWLanNotificationData = ^TWLanNotificationData;
  TWLanNotificationData = record
    NotificationSource: DWORD;
    NotificationCode: DWORD;
    InterfaceGuid: GUID;
    dwDataSize: DWORD;
    pData: PVOID;
  end;

  TWLanNotificationCallback = procedure(data: PWLanNotificationData; context: PVOID); stdcall;

function WlanOpenHandle(dwClientVersion: DWORD; pReserved: PVOID;
  out pdwNegotiatedVersion: DWORD; out phClientHandle: HANDLE): DWORD; stdcall;
  external wlanapi name 'WlanOpenHandle';

function WlanRegisterNotification(hClientHandle: HANDLE; dwNotifSource: DWORD;
  bIgnoreDuplicate: BOOL; funcCallback: TWLanNotificationCallback; pCallbackContext: PVOID;
  pReserved: PVOID; out pdwPrevNotifSource: DWORD): DWORD; stdcall;
  external wlanapi name 'WlanRegisterNotification';

并称他们为:

// Define a callback procedure to handle the notifications
// You can supply a context pointer to any user information the callback
// may require (pointer to object, etc)
procedure OnWlanNotify(data : PWLanNotificationData; context : PVOID); stdcall;
begin
  // ShowMessage(IntToStr(data^.NotificationCode));  etc...
end;

// Register for notification
procedure TForm1.FormCreate(Sender: TObject);
var
  negotiatedVer : DWORD;
  prevSource : DWORD
begin
  if WlanOpenHandle(2, nil, negotiatedVer, FHandle) <> ERROR_SUCCESS then begin
    // handle error...
  end;
  // check negotiatedVersion if needed
  if WlanRegisterNotification(FHandle,
                       WLAN_NOTIFICATION_SOURCE_ACM,
                       LongBool(true),
                       @OnWlanNotify,
                       nil,
                       nil,
                       prevSource) <> ERROR_SUCCESS then begin
  end;

这会为您注册 WLAN 通知。您的回调函数将在收到通知后执行,通知的性质可以在传递给该方法的 TWlanNotificationData 结构中找到。

您还应该取消注册不再需要的通知。我在这里只实现了基本的错误检查。可以在引用的 MSDN 文档中找到各种错误代码的详细信息。

ACM 通知的(部分)列表:

const
  WLAN_NOTIFICATION_ACM_AUTOCONF_ENABLED = [=12=]000001; 
    //Autoconfiguration is enabled.
  WLAN_NOTIFICATION_ACM_AUTOCONF_DISABLED = [=12=]000002;
    //Autoconfiguration is disabled.
  WLAN_NOTIFICATION_ACM_BACKGROUND_SCAN_ENABLED = [=12=]000003; 
    //Background scans are enabled.
  WLAN_NOTIFICATION_ACM_BACKGROUND_SCAN_DISABLED = [=12=]000004;
    //Background scans are disabled.
  WLAN_NOTIFICATION_ACM_BSS_TYPE_CHANGE = [=12=]000005;
    //The BSS type for an interface has changed.
  WLAN_NOTIFICATION_ACM_POWER_SETTING_CHANGE = [=12=]000006;
    //The power setting for an interface has changed.
  WLAN_NOTIFICATION_ACM_SCAN_COMPLETE = [=12=]000007;
    //A scan for networks has completed.
  WLAN_NOTIFICATION_ACM_SCAN_FAIL = [=12=]000008;
    //A scan for connectable networks failed.
  WLAN_NOTIFICATION_ACM_CONNECTION_START = [=12=]000009;
    //A connection has started to a network in range.
  WLAN_NOTIFICATION_ACM_CONNECTION_COMPLETE = [=12=]00000a;
    //A connection has completed.
  WLAN_NOTIFICATION_ACM_CONNECTION_ATTEMPT_FAIL = [=12=]00000b;
    //A connection attempt has failed.
  WLAN_NOTIFICATION_ACM_FILTER_LIST_CHANGE = [=12=]00000c;
    //A change in the filter list has occurred, either through group policy or a call to the WlanSetFilterList function.
  WLAN_NOTIFICATION_ACM_INTERFACE_ARRIVAL = [=12=]00000d;
    //A wireless LAN interface is been added to or enabled on the local computer.
  WLAN_NOTIFICATION_ACM_INTERFACE_REMOVAL = [=12=]00000e;
    //A wireless LAN interface has been removed or disabled on the local computer.
  WLAN_NOTIFICATION_ACM_PROFILE_CHANGE = [=12=]00000f;
    //A change in a profile or the profile list has occurred, either through group policy or by calls to Native Wifi functions.
  WLAN_NOTIFICATION_ACM_PROFILE_NAME_CHANGE = [=12=]000010;
    //A profile name has changed, either through group policy or by calls to Native Wifi functions.
  WLAN_NOTIFICATION_ACM_PROFILES_EXHAUSTED = [=12=]000011;
    //All profiles were exhausted in an attempt to autoconnect.
  WLAN_NOTIFICATION_ACM_NETWORK_NOT_AVAILABLE = [=12=]000012;
    //The wireless service cannot find any connectable network after a scan.
  WLAN_NOTIFICATION_ACM_NETWORK_AVAILABLE = [=12=]000013;
    //The wireless service found a connectable network after a scan, the interface was in the disconnected state, and there is no compatible auto-connect profile that the wireless service can use to connect .
  WLAN_NOTIFICATION_ACM_DISCONNECTING = [=12=]000014;
    //The wireless service is disconnecting from a connectable network.
  WLAN_NOTIFICATION_ACM_DISCONNECTED = [=12=]000015;
    //The wireless service has disconnected from a connectable network.
  WLAN_NOTIFICATION_ACM_ADHOC_NETWORK_STATE_CHANGE = [=12=]000016;
    //A state change has occurred for an adhoc network.

第二个示例回调更详细:

procedure OnWlanNotify(data : PWLanNotificationData; context : PVOID); stdcall;
begin
  case data^.NotificationCode of
    WLAN_NOTIFICATION_ACM_AUTOCONF_ENABLED : 
      TForm1(context^).Memo1.Lines.Add('Autoconfiguration is enabled.');
    WLAN_NOTIFICATION_ACM_AUTOCONF_DISABLED : 
      TForm1(context^).Memo1.Lines.Add('Autoconfiguration is disabled.');
    WLAN_NOTIFICATION_ACM_BACKGROUND_SCAN_ENABLED : 
      TForm1(context^).Memo1.Lines.Add('Background scans are enabled.');
    WLAN_NOTIFICATION_ACM_BACKGROUND_SCAN_DISABLED : 
      TForm1(context^).Memo1.Lines.Add('Background scans are disabled.');
    WLAN_NOTIFICATION_ACM_BSS_TYPE_CHANGE : 
      TForm1(context^).Memo1.Lines.Add('The BSS type for an interface has changed.');
    WLAN_NOTIFICATION_ACM_POWER_SETTING_CHANGE : 
      TForm1(context^).Memo1.Lines.Add('The power setting for an interface has changed.');
    WLAN_NOTIFICATION_ACM_SCAN_COMPLETE : 
      TForm1(context^).Memo1.Lines.Add('A scan for networks has completed.');
    WLAN_NOTIFICATION_ACM_SCAN_FAIL : 
      TForm1(context^).Memo1.Lines.Add('A scan for connectable networks failed.');
    WLAN_NOTIFICATION_ACM_CONNECTION_START : 
      TForm1(context^).Memo1.Lines.Add('A connection has started to a network in range.');
    WLAN_NOTIFICATION_ACM_CONNECTION_COMPLETE : 
      TForm1(context^).Memo1.Lines.Add('A connection has completed.');
    WLAN_NOTIFICATION_ACM_CONNECTION_ATTEMPT_FAIL : 
      TForm1(context^).Memo1.Lines.Add('A connection attempt has failed.');
    WLAN_NOTIFICATION_ACM_FILTER_LIST_CHANGE : 
      TForm1(context^).Memo1.Lines.Add('A change in the filter list has occurred, either through group policy or a call to the WlanSetFilterList function.');
    WLAN_NOTIFICATION_ACM_INTERFACE_ARRIVAL : 
      TForm1(context^).Memo1.Lines.Add('A wireless LAN interface is been added to or enabled on the local computer.');
    WLAN_NOTIFICATION_ACM_INTERFACE_REMOVAL : 
      TForm1(context^).Memo1.Lines.Add('A wireless LAN interface has been removed or disabled on the local computer.');
    WLAN_NOTIFICATION_ACM_PROFILE_CHANGE : 
      TForm1(context^).Memo1.Lines.Add('A change in a profile or the profile list has occurred, either through group policy or by calls to Native Wifi functions.');
    WLAN_NOTIFICATION_ACM_PROFILE_NAME_CHANGE : 
      TForm1(context^).Memo1.Lines.Add('A profile name has changed, either through group policy or by calls to Native Wifi functions.');
    WLAN_NOTIFICATION_ACM_PROFILES_EXHAUSTED : 
      TForm1(context^).Memo1.Lines.Add('All profiles were exhausted in an attempt to autoconnect.');
    WLAN_NOTIFICATION_ACM_NETWORK_NOT_AVAILABLE : 
      TForm1(context^).Memo1.Lines.Add('The wireless service cannot find any connectable network after a scan.');
    WLAN_NOTIFICATION_ACM_NETWORK_AVAILABLE : 
      TForm1(context^).Memo1.Lines.Add('The wireless service found a connectable network after a scan, the interface was in the disconnected state, and there is no compatible auto-connect profile that the wireless service can use to connect.');
    WLAN_NOTIFICATION_ACM_DISCONNECTING : 
      TForm1(context^).Memo1.Lines.Add('The wireless service is disconnecting from a connectable network.');
    WLAN_NOTIFICATION_ACM_DISCONNECTED : 
      TForm1(context^).Memo1.Lines.Add('The wireless service has disconnected from a connectable network.');
    WLAN_NOTIFICATION_ACM_ADHOC_NETWORK_STATE_CHANGE : 
      TForm1(context^).Memo1.Lines.Add('A state change has occurred for an adhoc network.');
  end;
end;

在上面的示例中,在用户上下文参数中传递了指向 Form1 的指针。这在回调中传回,允许您从方法中访问该数据。

  if WlanRegisterNotification(FHandle,
                           WLAN_NOTIFICATION_SOURCE_ACM,
                           LongBool(true),
                           @OnWlanNotify,
                           @Form1,  // Pass in form pointer
                           nil,
                           prevSource) <> ERROR_SUCCESS then begin
    // handle error
  end;