windows hooks in .net WH_CALLWNDPROC

[sdlangers]

Hi,

im tyring to use the windows api to hook another process (by injecting the function into the process) but the callback function does not fire.

ive been looking for .net versions of the calls but couldnt find any - so these are my conversions from vb6 - maybe i have some of the datatypes/structures wrong?

heres the code

#Region " Delegates "
    Private Delegate Function HookProcDelegate( _
        ByVal nCode As Integer, _
        ByVal wParam As Integer, _
        ByVal lParam As CWPSTRUCT) As Integer

    Private Delegate Function enumWindowsDelegate(ByVal hWnd As Integer, _
                                                 ByVal lParam As Integer) As Boolean

#End Region

#Region "Declarations - Constants"

    Private Const HC_ACTION As Integer = 0
    Private Const WH_KEYBOARD_LL As Integer = 13
    Private Const WM_KEYDOWN As Integer = &H100
    Private Const WM_KEYUP As Integer = &H101
    Private Const WM_SYSKEYDOWN As Integer = &H104
    Private Const WM_SYSKEYUP As Integer = &H105

    Private Const WH_CALLWNDPROC = 4
    Private Const WM_CREATE = &H1
    Private Const EM_REPLACESEL = &HC2


    Public Structure CWPSTRUCT
        Dim lParam As Integer
        Dim wParam As Integer
        Dim message As Integer
        Dim hwnd As Integer
    End Structure

    Public Enum HookConstants
        HC_ACTION = 0
        HC_GETNEXT = 1
        HC_SKIP = 2
        HC_NOREMOVE = 3
        HC_NOREM = HC_NOREMOVE
        HC_SYSMODALOFF = 5
        HC_SYSMODALON = 4
    End Enum
#End Region

#Region "Declarations - Win32 APIs"

    
    Private Declare Function SetWindowsHookEx Lib "user32" _
       Alias "SetWindowsHookExA" ( _
       ByVal idHook As Integer, _
       ByVal lpfn As HookProcDelegate, _
       ByVal hmod As Integer, _
       ByVal dwThreadId As Integer) As Integer

    Private Declare Function CallNextHookEx Lib "user32" ( _
        ByVal hHook As Integer, _
        ByVal nCode As Integer, _
        ByVal wParam As Integer, _
        ByVal lParam As CWPSTRUCT) As Integer

    Private Declare Function UnhookWindowsHookEx Lib "user32" ( _
        ByVal hHook As Integer) As Integer

    Private Declare Function GetWindowThreadProcessId Lib "user32" ( _
        ByVal hwnd As Integer, ByRef lpdwProcessId As Integer) As Integer

    Private Declare Function EnumWindows Lib "user32.dll" ( _
        ByVal lpEnumFunc As enumWindowsDelegate, ByVal lParam As Integer) As Integer

#End Region

    Public hModule As Integer
    Public hParent As Integer
    Public dwThreadID As Integer
    Public hHook As Integer
    
    Private hp As HookProcDelegate

    Public Function startCapture() As Boolean
        Dim processID As Integer  

        hModule = Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0)).ToInt32

         find the exe process threadid
        Dim p As Process

        For Each p In Process.GetProcesses()
            If p.ProcessName = "myExeToBeHooked.exe" Then
                processID = p.Id
                Exit For
            End If
        Next

         pass the process id to the enumWindows
        EnumWindows(AddressOf EnumWindowsProc, processID)

        hp = AddressOf CallWndProc

        hHook = SetWindowsHookEx(WH_CALLWNDPROC, hp, hModule, dwThreadID)

        Return True
    End Function

    Public Function EnumWindowsProc(ByVal HWND As Integer, ByVal LPARAM As Integer) As Boolean
        Dim dwProcessID As Integer

        dwThreadID = GetWindowThreadProcessId(HWND, dwProcessID)

        If dwProcessID = LPARAM Then
            hParent = HWND            
            Return False
        End If

        Return True
    End Function

    Public Function CallWndProc(ByVal nCode As Integer, ByVal wParam As Integer, ByVal lParam As CWPSTRUCT) As Integer
         this does not fire
        Return (CallNextHookEx(0, nCode, wParam, lParam))
    End Function

    Public Function stopCapture() As Boolean
         Remove the hook
        If hHook <> 0 Then
            UnhookWindowsHookEx(hHook)
        End If

        Return True
    End Function