VBA and GetRawInputDeviceList - vba

Question

I am working in Access 2013 and try to get GetRawInputDeviceList, GetRawInputDeviceInfo, RegisterRawInputDevices and GetRawInputData equivalents for VBA with no success. I have also searched in vain for a procedure, function or module to get a list of connected HID devices to a computer to pick out a barcode scanner. This is the beginning of the third week so I am on my knees begging for assistance. Do any of you all have a module you're willing to share, a link to a website where this is dealt with? Any help is greatly appreciated.

Answer 1

Using the GetRawInputDeviceList API from VBA would be pretty tricky because of the pRawInputDeviceList parameter. Unless you're willing to jump through a ton of hoops to manage your own memory and manually handle the resulting array of RAWINPUTDEVICELIST in raw memory, you'll be better off coming at this from another direction.
Most barcode scanners I've dealt with present themselves to Windows as a keyboard. One possible solution would be to use a WMI query to enumerate attached Win32_Keyboard devices:
Private Sub ShowKeyboardInfo()
Dim WmiServer As Object
Dim ResultSet As Object
Dim Keyboard As Object
Dim Query As String
Query = "SELECT * From Win32_Keyboard"
Set WmiServer = GetObject("winmgmts:root/CIMV2")
Set ResultSet = WmiServer.ExecQuery(Query)
For Each Keyboard In ResultSet
Debug.Print Keyboard.Name & vbTab & _
Keyboard.Description & vbTab & _
Keyboard.DeviceID & vbTab & _
Keyboard.Status
Next Keyboard
End Sub
Note: If it doesn't turn up there, you can enumerate all of the USB devices by querying CIM_USBDevice: Query = "SELECT * From Win32_Keyboard"
EDIT: Per the comments, the above code won't return the handle needed to register to receive raw input events. This should get you started though - the RegisterRawInputDevices and GetRawInputData aspects are beyond the scope of what will easily go in an answer. Take a hack at it, and if you run into any problems post your code in another question.
Declarations:
Private Type RawInputDeviceList
hDevice As Long
dwType As Long
End Type
Private Type RidKeyboardInfo
cbSize As Long
dwType As Long
dwKeyboardMode As Long
dwNumberOfFunctionKeys As Long
dwNumberOfIndicators As Long
dwNumberOfKeysTotal As Long
End Type
Private Enum DeviceType
TypeMouse = 0
TypeKeyboard = 1
TypeHID = 2
End Enum
Private Enum DeviceCommand
DeviceName = &H20000007
DeviceInfo = &H2000000B
PreParseData = &H20000005
End Enum
Private Declare Function GetRawInputDeviceList Lib "user32" ( _
ByVal pRawInputDeviceList As Long, _
ByRef puiNumDevices As Long, _
ByVal cbSize As Long) As Long
Private Declare Function GetRawInputDeviceInfo Lib "user32" Alias "GetRawInputDeviceInfoW" ( _
ByVal hDevice As Long, _
ByVal uiCommand As Long, _
ByVal pData As Long, _
ByRef pcbSize As Long) As Long
Private Declare Function GetLastError Lib "kernel32" () As Long
Sample of retrieving device names with GetRawInputDeviceInfo:
Private Sub SampleCode()
Dim devices() As RawInputDeviceList
devices = GetRawInputDevices
Dim i As Long
For i = 0 To UBound(devices)
'Inspect the type - only looking for a keyboard.
If devices(i).dwType = TypeKeyboard Then
Dim buffer As String
Dim size As Long
'First call with a null pointer returns the string length in size.
If GetRawInputDeviceInfo(devices(i).hDevice, DeviceName, 0&, size) = -1 Then
Debug.Print "GetRawInputDeviceInfo error " & GetLastError()
Else
'Size the string buffer.
buffer = String(size, Chr$(0))
'The second call copies the name into the passed buffer.
If GetRawInputDeviceInfo(devices(i).hDevice, DeviceName, StrPtr(buffer), size) = -1 Then
Debug.Print "GetRawInputDeviceInfo error " & GetLastError()
Else
Debug.Print buffer
End If
End If
End If
Next i
End Sub
Private Function GetRawInputDevices() As RawInputDeviceList()
Dim devs As Long
Dim output() As RawInputDeviceList
'First call with a null pointer returns the number of devices in devs
If GetRawInputDeviceList(0&, devs, LenB(output(0))) = -1 Then
Debug.Print "GetRawInputDeviceList error " & GetLastError()
Else
'Size the output array.
ReDim output(devs - 1)
'Second call actually fills the array.
If GetRawInputDeviceList(VarPtr(output(0)), devs, LenB(output(0))) = -1 Then
Debug.Print "GetRawInputDeviceList error " & GetLastError()
Else
GetRawInputDevices = output
End If
End If
End Function
Sorry about the side scrolling.