Hi,

I'm trying to read raw input from a HID-device. I have tried both C# and
VB.NET with no success.

Right now I'm trying to list the raw input devices using
GETRAWINPUTDEVICELIST. My problem, I think, is that the function
GETRAWINPUTDEVICELIST needs a pointer to a structure called RAWINPUTDEVICE,
and I have no clue how to provide this.  I think this is the problem,
because right now I can get the number of devices connected to the system,
but when I try to get the list of devices, I don't get any errors, just an
empty structure of RAWINPUTDEVICE.

If anyone could shed any light on this subject, I would greatly appreciate
it.

I have included my code below, Thanks!
David
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---------------------------------

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)> _
Public Structure RAWINPUTDEVICELIST

   ' Handle to the raw input device
   Public hDevice As Int32

   ' Type of device
   Public dwType As Int32

End Structure

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---------------------------------

Public Declare Function GetRawInputDeviceList Lib "user32.dll" _
       (ByVal pRawInputDeviceList() As RAWINPUTDEVICELIST, _
        ByRef puiNumDevices As Integer, _
        ByVal cbSize As Integer) _
       As Integer

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---------------------------------

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Handles MyBase.Load

       Try

           Getdevices()

       Catch ex As Exception
           Data.Text = "Exception: " & ex.Message
       End Try

   End Sub

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---------------------------------

Public Sub GetDevices()

   ' used only to get the size of 1 RAWINPUTDEVICELIST
   Dim Device As RawInput.RAWINPUTDEVICELIST

   Dim DeviceList(0) As RawInput.RAWINPUTDEVICELIST
   Dim DeviceCount As Integer

   ' Get the number of devices connected
   Dim Result As Integer = RawInput.GetRawInputDeviceList(Nothing,
NumDevices, Marshal.SizeOf(DeviceList(0)))

   If Not Result = 0 Then
       Dim ErrorCode As Integer = Marshal.GetLastWin32Error
       Data.Text = "Error " & ErrorCode & ". " & GetMessage(ErrorCode)
       Exit Sub
   End If

   ' Allocate the memory needed
   ReDim DeviceList(NumDevices - 1)

   ' ----------------------------------------------------------------------

   ' Attempt 1 to retrieve all devices
   ' This attempt failed
   Result = RawInput.GetRawInputDeviceList(DeviceList,
Marshal.SizeOf(Device) * NumDevices, Marshal.SizeOf(Device))

   ' ----------------------------------------------------------------------

   ' Attempt 2 to retrieve all devices
   ' This attempt also failed
   ' I removed attempt 2 in pasting this code.

   ' ----------------------------------------------------------------------

   Select Case Result

       Case -1
           ' Error occurred, display what happened
           Dim ErrorCode As Integer = Marshal.GetLastWin32Error
           Data.Text = "Error " & ErrorCode & ". " & GetMessage(ErrorCode)

       Case 0
           ' DO NOTHING

       Case Else
           Data.AppendText("Retrieved " & Result & " devices..." & vbCrLf)

           For Each dvc As RawInput.RAWINPUTDEVICELIST In DeviceList
               Data.AppendText("hDevice: " & dvc.hDevice.ToString & " ...
dwType: " & dvc.dwType & vbCrLf)
           Next dvc

   End Select

End Sub

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---------------------------------

Here is a copy of the output I get from Data.Text:
Retrieved 4 devices...
hDevice: 0 ... dwType: 0
hDevice: 0 ... dwType: 0
hDevice: 0 ... dwType: 0
hDevice: 0 ... dwType: 0

As I see it, the application can "see" that there are 4 devices attached to
my system, which is correct, but the
structure DeviceList() is not being popuplated with the data I need. Thanks!