Unbalanced Stack?

[Chris]

I use the following keyboard hook to stop some windows functions. VS2005

This line is giving me the following error. Anyone know why or how to
fix it. As far as I can tell my functions are declared correctly.

Return CallNextHookEx(KeyboardHandle, Code, wParam, lParam)

PInvokeStackImbalance was detected
Message: A call to PInvoke function
'Utility!Utility.LowLevelKBHook::CallNextHookEx' has unbalanced the
stack. This is likely because the managed PInvoke signature does not
match the unmanaged target signature. Check that the calling convention
and parameters of the PInvoke signature match the target unmanaged
signature.


This is the class that i am using to do this. To duplicate the error
just create a new form, create a new LowLevelKBHook object and then
press a key. You'll get the error. Thanks.

Chris

Imports System.Runtime.InteropServices
Imports System.Reflection
Imports System.Drawing
Imports System.Threading

Public Class LowLevelKBHook
Public Declare Function UnhookWindowsHookEx Lib "user32" _
(ByVal hHook As Integer) As Integer

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

Private Declare Function GetAsyncKeyState Lib "user32" _
(ByVal vKey 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 KBDLLHOOKSTRUCT) As Integer

Public Structure KBDLLHOOKSTRUCT
Public vkCode As Integer
Public scanCode As Integer
Public flags As Integer
Public time As Integer
Public dwExtraInfo As Integer
End Structure

' Low-Level Keyboard Constants
Private Const HC_ACTION As Integer = 0
Private Const LLKHF_EXTENDED As Integer = &H1
Private Const LLKHF_INJECTED As Integer = &H10
Private Const LLKHF_ALTDOWN As Integer = &H20
Private Const LLKHF_UP As Integer = &H80

' Virtual Keys
Public Const VK_TAB As Integer = &H9
Public Const VK_CONTROL As Integer = &H11
Public Const VK_ESCAPE As Integer = &H1B
Public Const VK_DELETE As Integer = &H2E

Private Const WH_KEYBOARD_LL As Integer = 13&
Public KeyboardHandle As Integer


' Implement this function to block as many
' key combinations as you'd like
Sub New()
Me.HookKeyboard()
End Sub

Public Function IsHooked( _
ByRef Hookstruct As KBDLLHOOKSTRUCT) As Boolean

Debug.WriteLine("Hookstruct.vkCode: " & Hookstruct.vkCode)
Debug.WriteLine(Hookstruct.vkCode = VK_ESCAPE)
Debug.WriteLine(Hookstruct.vkCode = VK_TAB)

If (Hookstruct.vkCode = VK_ESCAPE) And _
CBool(GetAsyncKeyState(VK_CONTROL) _
And &H8000) Then

Call HookedState("Ctrl + Esc blocked")
Return True
End If

If (Hookstruct.vkCode = VK_TAB) And _
CBool(Hookstruct.flags And _
LLKHF_ALTDOWN) Then

Call HookedState("Alt + Tab blockd")
Return True
End If

If (Hookstruct.vkCode = VK_ESCAPE) And _
CBool(Hookstruct.flags And _
LLKHF_ALTDOWN) Then

Call HookedState("Alt + Escape blocked")
Return True
End If

Return False
End Function

Private Sub HookedState(ByVal Text As String)
Debug.WriteLine(Text)
End Sub

Public Function KeyboardCallback(ByVal Code As Integer, _
ByVal wParam As Integer, _
ByRef lParam As KBDLLHOOKSTRUCT) As Integer

If (Code = HC_ACTION) Then
Debug.WriteLine("Calling IsHooked")

If (IsHooked(lParam)) Then
Return 1
End If

End If

Return CallNextHookEx(KeyboardHandle, _
Code, wParam, lParam)

End Function


Public Delegate Function KeyboardHookDelegate( _
ByVal Code As Integer, _
ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) _
As Integer

<MarshalAs(UnmanagedType.FunctionPtr)> _
Private callback As KeyboardHookDelegate

Public Sub HookKeyboard()
callback = New KeyboardHookDelegate(AddressOf KeyboardCallback)

KeyboardHandle = SetWindowsHookEx( _
WH_KEYBOARD_LL, callback, _
Marshal.GetHINSTANCE( _
[Assembly].GetExecutingAssembly.GetModules()(0)).ToInt32, 0)

Call CheckHooked()
End Sub

Public Sub CheckHooked()
If (Hooked()) Then
Debug.WriteLine("Keyboard hooked")
Else
Debug.WriteLine("Keyboard hook failed: " & Err.LastDllError)
End If
End Sub

Private Function Hooked() As Boolean
Hooked = KeyboardHandle <> 0
End Function

Public Sub UnhookKeyboard()
If (Hooked()) Then
Call UnhookWindowsHookEx(KeyboardHandle)
End If
End Sub

End Class

 

[Herfried K. Wagner [MVP]]

I use the following keyboard hook to stop some windows functions. VS2005

This line is giving me the following error. Anyone know why or how to
fix it. As far as I can tell my functions are declared correctly.

Return CallNextHookEx(KeyboardHandle, Code, wParam, lParam)

PInvokeStackImbalance was detected
Message: A call to PInvoke function
'Utility!Utility.LowLevelKBHook::CallNextHookEx' has unbalanced the
stack. This is likely because the managed PInvoke signature does not
match the unmanaged target signature. Check that the calling convention
and parameters of the PInvoke signature match the target unmanaged
signature.
[...]
Private Declare Function CallNextHookEx Lib "user32" _
(ByVal hHook As Integer, _
ByVal nCode As Integer, _
ByVal wParam As Integer, _
ByVal lParam As KBDLLHOOKSTRUCT) As Integer

=> 'ByRef lParam As KBDLLHOOKSTRUCT'.

 

[Chris]

I use the following keyboard hook to stop some windows functions. VS2005

This line is giving me the following error. Anyone know why or how to
fix it. As far as I can tell my functions are declared correctly.

Return CallNextHookEx(KeyboardHandle, Code, wParam, lParam)

PInvokeStackImbalance was detected
Message: A call to PInvoke function
'Utility!Utility.LowLevelKBHook::CallNextHookEx' has unbalanced the
stack. This is likely because the managed PInvoke signature does not
match the unmanaged target signature. Check that the calling
convention and parameters of the PInvoke signature match the target
unmanaged signature.
[...]
Private Declare Function CallNextHookEx Lib "user32" _
(ByVal hHook As Integer, _
ByVal nCode As Integer, _
ByVal wParam As Integer, _
ByVal lParam As KBDLLHOOKSTRUCT) As Integer

=> 'ByRef lParam As KBDLLHOOKSTRUCT'.

Thanks...