Refresh WiFi network list with 'WlanScan' (convert api syntax from c# to vba... or a workaround?)

Question

I need to refresh Window's list of wireless networks.

I'll gladly accept any workaround that I can automate (cmdline, wmi, etc) directly or indirectly from VBA. (I'm using Windows 7 Home 64-bit with Office 365 Pro 64-bit.)

I can list the networks programmatically a couple ways including netsh, or the code below, but the list does not refresh unless I physically click the Network Connection icon on the taskbar's Notification area.

• The list does not auto-update every 60 seconds as some docs state.
• Disconnect+Reconnecting the NIC is not a feasible/sustainable option.

I think I'm not getting the handle from WlanOpenHandle as required and I'm green at converting C to VBA.

No errors but WlanScan returns unknown code 1168.

• I adapted from the VB version here: wlanscan (wlanapi)
• MSDN documentation: WlanScan function

---

Related bits:

Here's the function declaration for VB, adapted:

Public Shared Function WlanScan(ByVal hClientHandle As IntPtr, _
   ByRef pInterfaceGuid As Guid, ByVal pDot11Ssid As IntPtr, _
   ByVal pIeData As IntPtr, ByVal pReserved As IntPtr) As UInteger
End Function

...and an example of function usage in C#:

Guid g;
//wlanHndl is the handle returned previously by calling [WlanOpenHandle]
for (int i = 0; i < infoList.dwNumberOfItems; i++)
{
g = infoList.InterfaceInfo[i].InterfaceGuid;
uint resultCode=WlanScan(wlanHndl, ref g, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);
if (resultCode != 0)
    return;
}

...and how to open the handle, in C++ (from here):

dwResult = WlanOpenHandle(dwMaxClient, NULL, &dwCurVersion, &hClient);
if (dwResult != ERROR_SUCCESS) {
    wprintf(L"WlanOpenHandle failed with error: %u\n", dwResult);
    return 1;
    // You can use FormatMessage here to find out why the function failed
}

---

_"Un-hidden:"

Obtain (cached) list of wireless networks:

The code to list the networks works great - except for not refreshing on it's own. (Previously I was parsing the text output of netsh wlan show networks mode=bssid, which had the same issue.)

I had previously removed this section because its lengthy and seems to work fine except for the refresh. -)

Option Explicit  'section's source: vbforums.com/showthread.php?632731
Private Const DOT11_SSID_MAX_LENGTH As Long = 32
Private Const WLAN_MAX_PHY_TYPE_NUMBER As Long = 8
Private Const WLAN_AVAILABLE_NETWORK_CONNECTED As Long = 1
Private Const WLAN_AVAILABLE_NETWORK_HAS_PROFILE As Long = 2

Private Type GUID  'from cpearson.com
    Data1 As Long: Data2 As Integer:  Data3 As Integer:  Data4(7) As Byte
End Type

Private Type WLAN_INTERFACE_INFO
    ifGuid As GUID: InterfaceDescription(255) As Byte: IsState As Long
End Type

Private Type DOT11_SSID
    uSSIDLength As Long:            ucSSID(DOT11_SSID_MAX_LENGTH - 1) As Byte
End Type

Private Type WLAN_AVAILABLE_NETWORK
    strProfileName(511) As Byte:    dot11Ssid As DOT11_SSID
    dot11BssType As Long:           uNumberOfBssids As Long
    bNetworkConnectable As Long:    wlanNotConnectableReason As Long
    uNumberOfPhyTypes As Long:      dot11PhyTypes(WLAN_MAX_PHY_TYPE_NUMBER - 1) As Long
    bMorePhyTypes As Long:          wlanSignalQuality As Long
    bSEcurityEnabled As Long:       dot11DefaultAuthAlgorithm As Long
    dot11DefaultCipherAlgorithm As Long: dwflags As Long: dwReserved As Long
End Type

Private Type WLAN_INTERFACE_INFO_LIST
    dwNumberOfItems As Long: dwIndex As Long: InterfaceInfo As WLAN_INTERFACE_INFO
End Type

Private Type WLAN_AVAILABLE_NETWORK_LIST
    dwNumberOfItems As Long:  dwIndex As Long: Network As WLAN_AVAILABLE_NETWORK
End Type

Declare PtrSafe Function WlanOpenHandle Lib "Wlanapi.dll" (ByVal dwClientVersion As Long, _
                ByVal pdwReserved As Long, ByRef pdwNegotiaitedVersion As Long, _
                ByRef phClientHandle As Long) As Long

Declare PtrSafe Function WlanEnumInterfaces Lib "Wlanapi.dll" (ByVal hClientHandle As Long, _
                ByVal pReserved As Long, ppInterfaceList As Long) As Long

Declare PtrSafe Function WlanGetAvailableNetworkList Lib "Wlanapi.dll" ( _
                ByVal hClientHandle As Long, pInterfaceGuid As GUID, ByVal dwflags As Long, _
                ByVal pReserved As Long, ppAvailableNetworkList As Long) As Long

Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, _
                Source As Any, ByVal Length As Long)

Declare PtrSafe Sub WlanFreeMemory Lib "Wlanapi.dll" (ByVal pMemory As Long)

Type WiFis
  ssid As String: signal As Single
End Type

Public Function GetWiFi() As WiFis()
'returns an array of custom type WiFis (1st interface only)

    Dim udtList As WLAN_INTERFACE_INFO_LIST, udtAvailList As WLAN_AVAILABLE_NETWORK_LIST, udtNetwork As WLAN_AVAILABLE_NETWORK
    Dim lngReturn As Long, lngHandle As Long, lngVersion As Long, lngList As Long, lngAvailable As Long
    Dim lngStart As Long, intCount As Integer, ssid As String, signal As Single, wifiOut() As WiFis
    n = 0

    lngReturn = WlanOpenHandle(2&, 0&, lngVersion, lngHandle) 'get handle
    If lngReturn <> 0 Then
        Debug.Print "Couldn't get wlan handle (Code " & lngReturn & ")"
        Exit Function
    End If

    lngReturn = WlanEnumInterfaces(ByVal lngHandle, 0&, lngList) 'enumerate <*first interface only*>
    CopyMemory udtList, ByVal lngList, Len(udtList)
    lngReturn = WlanGetAvailableNetworkList(lngHandle, udtList.InterfaceInfo.ifGuid, 2&, 0&, lngAvailable) 'get network list
    CopyMemory udtAvailList, ByVal lngAvailable, LenB(udtAvailList)
    intCount = 0
    lngStart = lngAvailable + 8

    Do
        CopyMemory udtNetwork, ByVal lngStart, Len(udtNetwork) ' Populate avail. network structure
        ssid = Replace(StrConv(udtNetwork.dot11Ssid.ucSSID, vbUnicode), Chr(0), "")
        If Len(ssid) < 4 Then ssid = "(Unnamed)"
        signal = CSng(udtNetwork.wlanSignalQuality) / 100
        '[Signal] = 0 to 100 which represents the signal strength (100 Signal)=(-100dBm RSSI), (100 Signal)=(-50dBm RSSI)

        If udtNetwork.dwflags = 0 Then
            n = n + 1
            ReDim Preserve wifiOut(n)
            wifiOut(n).ssid = ssid
            wifiOut(n).signal = signal
        Else
            'skipping networks with [dwflags] > 0
            'I *think* that's what I'm supposed to do
            'Returns 3 for currently connected network, 2 for networks that have profiles
        End If

        intCount = intCount + 1
        lngStart = lngStart + Len(udtNetwork)
    Loop Until intCount = udtAvailList.dwNumberOfItems
    WlanFreeMemory lngAvailable     'clean up memory
    WlanFreeMemory lngList

    GetWiFi = wifiOut   'Success! (function is populated with cached network list)

End Function

---

_{...and the problem:}

Refresh network list using WlanScan?

This does not generate a VBA error, but does return code 1168 (which I can't identify)/ (Source)

'Added blindly:'wlanui type library (wlanui.dll) and "wlan pref iua" (wlanconn.dll)

Public Type DOT11_SSID 
   uSSIDLength As LongPtr: ucSSID As String
End Type

Private Type GUID 'from cpearson.com/excel/CreateGUID.aspx
    Data1 As LongPtr: Data2 As Integer
    Data3 As Integer: Data4(0 To 7) As Byte
End Type

#If Win64 Then 'also new to Office-64bit, but seems okay
    Declare PtrSafe Function WlanScan Lib "Wlanapi.dll" _
        (ByVal hClientHandle As LongPtr, ByRef pInterfaceGuid As GUID, _
        ByVal pDot11Ssid As LongPtr, ByVal pIeData As LongPtr, _
        ByVal pReserved As LongPtr) As LongPtr
#Else
    Private Declare WlanScan Lib "Wlanapi.dll" _
        (ByVal hClientHandle As LongPtr, ByRef pInterfaceGuid As GUID, _
        ByVal pDot11Ssid As LongPtr, ByVal pIeData As LongPtr, _
        ByVal pReserved As LongPtr) As LongPtr
#End If

Sub test_RefreshNetworkList()
    Dim hresult As LongPtr, phClientHandle As Long, pdwNegotiatedVersion As Long
    Dim retVal As Longptr, g As GUID
    hresult = WlanOpenHandle(2&, 0&, pdwNegotiatedVersion, phClientHandle)
    retVal = WlanScan(phClientHandle, g, 0, 0, 0)
    Select Case retVal
        Case 87: Debug.Print "ERROR_INVALID_PARAMETER"
        Case 6: Debug.Print "ERROR_INVALID_HANDLE"
        Case 8: Debug.Print "ERROR_NOT_ENOUGH_MEMORY"
        Case Else: Debug.Print "RPC_STATUS : " & retVal  ' "misc errors"
    End Select
End Sub

---

Surely there's a roundabout way to refresh the network list from VBA? I'm cool with workarounds that I can automate... anything?!

Thanks!

---

Edit:

I changed Long to LongPtr in the applicable (I think) spots. Same error.

Here's the WlanOpenHandle and WlanScan definitions.

Declare PtrSafe Function WlanOpenHandle Lib "Wlanapi.dll" 
    (ByVal dwClientVersion As LongPtr, _
     ByVal pdwReserved As LongPtr, 
     ByRef pdwNegotiaitedVersion As LongPtr, _
     ByRef phClientHandle As LongPtr           ) As LongPtr

(...it was also my first attempt time using compiler constants.)

#If Win64 Then
    Declare PtrSafe Function WlanScan Lib "Wlanapi.dll" _
        (ByVal hClientHandle As LongPtr,
         ByRef pInterfaceGuid As GUID, _
         ByVal pDot11Ssid As LongPtr, 
         ByVal pIeData As LongPtr, _
         ByVal pReserved As LongPtr) As LongPtr
#Else
    Private Declare WlanScan Lib "Wlanapi.dll" _
        (ByVal hClientHandle As LongPtr, 
         ByRef pInterfaceGuid As GUID, _
         ByVal pDot11Ssid As LongPtr, 
         ByVal pIeData As LongPtr, _
         ByVal pReserved As LongPtr     ) As LongPtr
#End If

Answer 1

I think your main problem with not refreshing is that you're never closing your open handles. This can cause problems, as there shouldn't be multiple open handles afaik.

You use WlanOpenHandle to gain a handle to the interface, but after you're done with it and have the information you need, you should call WlanCloseHandle to close that handle and the associated connection.

Declare PtrSafe Function WlanCloseHandle Lib "Wlanapi.dll" ( _
  ByVal hClientHandle As LongPtr, _
  Optional ByVal pReserved As LongPtr) As Long

And at then end of your function:

    WlanCloseHandle lngHandle 'Close handle
    GetWiFi = wifiOut   'Success! (function is populated with cached network list)
End Function

Any error handler, if you're going to add one, should test if the handle isn't 0, and if it isn't, close it.

I've also changed various little things, such as using LongPtr for pointers to make your code 64-bit compatible (note: it's not VBA6 compatible, that requires a lot of conditional compilations), reworking your declarations to not use optional parameters, and some other little things.

I've tested the following code with 10 iterations on a device and got 10 different results:

Code:

Public Function GetWiFi() As wifis()
'returns an array of custom type WiFis (1st interface only)

    Dim udtList As WLAN_INTERFACE_INFO_LIST, udtAvailList As WLAN_AVAILABLE_NETWORK_LIST, udtNetwork As WLAN_AVAILABLE_NETWORK
    Dim lngReturn As Long, pHandle As LongPtr, lngVersion As Long, pList As LongPtr, pAvailable As LongPtr
    Dim pStart As LongPtr, intCount As Integer, ssid As String, signal As Single, wifiOut() As wifis
    Dim n As Long
    n = 0

    lngReturn = WlanOpenHandle(2&, 0&, lngVersion, pHandle) 'get handle
    If lngReturn <> 0 Then
        Debug.Print "Couldn't get wlan handle (Code " & lngReturn & ")"
        Exit Function
    End If

    lngReturn = WlanEnumInterfaces(ByVal pHandle, 0&, pList) 'enumerate <*first interface only*>
    CopyMemory udtList, ByVal pList, Len(udtList)
    lngReturn = WlanScan(pHandle, udtList.InterfaceInfo.ifGuid)
    lngReturn = WlanGetAvailableNetworkList(pHandle, udtList.InterfaceInfo.ifGuid, 2&, 0&, pAvailable) 'get network list
    CopyMemory udtAvailList, ByVal pAvailable, LenB(udtAvailList)
    intCount = 0
    pStart = pAvailable + 8

    Do
        CopyMemory udtNetwork, ByVal pStart, Len(udtNetwork) ' Populate avail. network structure
        ssid = Replace(StrConv(udtNetwork.dot11Ssid.ucSSID, vbUnicode), Chr(0), "")
        If Len(ssid) < 4 Then ssid = "(Unnamed)"
        signal = CSng(udtNetwork.wlanSignalQuality) / 100
        '[Signal] = 0 to 100 which represents the signal strength (100 Signal)=(-100dBm RSSI), (100 Signal)=(-50dBm RSSI)

        If udtNetwork.dwflags = 0 Then
            n = n + 1
            ReDim Preserve wifiOut(n)
            wifiOut(n).ssid = ssid
            wifiOut(n).signal = signal
        Else
            'skipping networks with [dwflags] > 0
            'I *think* that's what I'm supposed to do
            'Returns 3 for currently connected network, 2 for networks that have profiles
        End If

        intCount = intCount + 1
        pStart = pStart + Len(udtNetwork)
    Loop Until intCount = udtAvailList.dwNumberOfItems
    WlanFreeMemory pAvailable     'clean up memory
    WlanFreeMemory pList
    WlanCloseHandle pHandle 'Close handle
    GetWiFi = wifiOut   'Success! (function is populated with cached network list)
End Function

Types and constants:

Private Const DOT11_SSID_MAX_LENGTH As Long = 32
Private Const WLAN_MAX_PHY_TYPE_NUMBER As Long = 8
Private Const WLAN_AVAILABLE_NETWORK_CONNECTED As Long = 1
Private Const WLAN_AVAILABLE_NETWORK_HAS_PROFILE As Long = 2

Public Type GUID
    Data(15) As Byte
End Type

Private Type WLAN_INTERFACE_INFO
    ifGuid As GUID: InterfaceDescription(255) As Byte: IsState As Long
End Type

Private Type DOT11_SSID
    uSSIDLength As Long:            ucSSID(DOT11_SSID_MAX_LENGTH - 1) As Byte
End Type

Private Type WLAN_AVAILABLE_NETWORK
    strProfileName(511) As Byte:    dot11Ssid As DOT11_SSID
    dot11BssType As Long:           uNumberOfBssids As Long
    bNetworkConnectable As Long:    wlanNotConnectableReason As Long
    uNumberOfPhyTypes As Long:      dot11PhyTypes(WLAN_MAX_PHY_TYPE_NUMBER - 1) As Long
    bMorePhyTypes As Long:          wlanSignalQuality As Long
    bSEcurityEnabled As Long:       dot11DefaultAuthAlgorithm As Long
    dot11DefaultCipherAlgorithm As Long: dwflags As Long: dwReserved As Long
End Type

Private Type WLAN_INTERFACE_INFO_LIST
    dwNumberOfItems As Long: dwIndex As Long: InterfaceInfo As WLAN_INTERFACE_INFO
End Type

Private Type WLAN_AVAILABLE_NETWORK_LIST
    dwNumberOfItems As Long:  dwIndex As Long: Network As WLAN_AVAILABLE_NETWORK
End Type

Public Type WiFis
  ssid As String: signal As Single
End Type

Function declarations:

Declare PtrSafe Function WlanOpenHandle Lib "Wlanapi.dll" (ByVal dwClientVersion As Long, _
                ByVal pdwReserved As LongPtr, ByRef pdwNegotiaitedVersion As Long, _
                ByRef phClientHandle As LongPtr) As Long

Declare PtrSafe Function WlanEnumInterfaces Lib "Wlanapi.dll" (ByVal hClientHandle As LongPtr, _
                ByVal pReserved As LongPtr, ByRef ppInterfaceList As LongPtr) As Long

Declare PtrSafe Function WlanGetAvailableNetworkList Lib "Wlanapi.dll" ( _
                ByVal hClientHandle As LongPtr, ByRef pInterfaceGuid As GUID, ByVal dwflags As Long, _
                ByVal pReserved As LongPtr, ByRef ppAvailableNetworkList As LongPtr) As Long


Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, _
                Source As Any, ByVal Length As Long)

Declare PtrSafe Function WlanScan Lib "Wlanapi.dll" _
        (ByVal hClientHandle As LongPtr, ByRef pInterfaceGuid As GUID, _
        Optional ByVal pDot11Ssid As LongPtr, Optional ByVal pIeData As LongPtr, _
        Optional ByVal pReserved As LongPtr) As Long

Declare PtrSafe Function WlanCloseHandle Lib "Wlanapi.dll" ( _
  ByVal hClientHandle As LongPtr, _
  Optional ByVal pReserved As LongPtr) As Long


Declare PtrSafe Sub WlanFreeMemory Lib "Wlanapi.dll" (ByVal pMemory As LongPtr)

Test call to print the list:

Public Sub PrintWifis()
    Dim aWifis() As wifis
    aWifis = GetWiFi
    Dim l As Long
    For l = LBound(aWifis) To UBound(aWifis)
        Debug.Print aWifis(l).ssid; aWifis(l).signal
    Next
End Sub

Answer 2

Regarding these comments:

the list does not refresh unless I physically click the Network Connection icon

and

Surely there's a roundabout way to refresh the network list from VBA? I'm cool with workarounds that I can automate... anything?!

Here's a roundabout way: programmatically click the Network Connection Icon:

Sub ClickIt()
With CreateObject("WScript.Shell")
    .Run "%windir%\explorer.exe ms-availablenetworks:"
End With
End Sub

You 'could' close it with a mouse_event after an application.wait when it takes some time to refresh