disable windows, ctrl, alt, del key

[d_rev]

This semester I have task to build an internet kiosk software. But, I face difficulty to start it. I don't know how to disable and enable windows key, ctrl+alt+del key, and the alt+tab key.
Is there anyone know how to do that??? I'm using vb.net 2008.
I'll very appreciate for your help. Thanks

[cjard]

write your own msgina.dll to process the low level interrupt emitted by those keys

Or just rip the Alt key off the keyboard. It's a lot easier

[SomE]

My solution:
Depending on what control it is, say a RichTextBox, you can handle the KeyDown/Up/Press events.

Private Sub rtb_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles rtb.KeyDown
        If e.KeyCode = Keys.Enter Then 'blocks the enter key
            e.Handled = True
        EndIf
End Sub

[GremlinSA]

Alt - Ctrl - Del, is a system event and cannot be locked, however the rest can and have been done, search the forum and you will find answers..

Gremmy..

[HenrikLaholm]

I have just done a kioskprogram that works on Windows XP.

To disable buttons you only add a Scancode map to the registry.
See http://www.microsoft.com/whdc/archive/w2kscan-map.mspx.
That will not block ctrl-alt-del, even if you disable those buttons.

The ctrl-alt-del event is handled in msgina.dll. A lot of other things are also hanled in that dll. To disable CTRL-ALT-DEL on WinXP you need to write your own gina.dll. The idea is to pass everything through to msgina.dll except for when CTRL-ALT-DEL is handled.

You can download a ginastub from Microsoft in a Platform SDK. There is an example but it's not complete.

You could have my code, if I only knew where to send it.

[HanneSThEGreaT]

What I did once was to create a keyboard hook, like :

'system hook libraries
Imports System.Runtime.InteropServices 'MarshalAs, Marshal
Imports System.Reflection 'assembly
'''''''''''''''''''''''''''''''

Public Class frmJolt
    Inherits System.Windows.Forms.Form

    ''''''''''''''''''''''''''''''''''''''''''''''''''''
    'disable  alt+tab and ctrl+esc  and alt esc system keys
    Private 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 = &H9
    Public Const VK_CONTROL = &H11
    Public Const VK_ESCAPE = &H1B
    Public Const VK_DELETE = &H2E
    Public Const VK_MENU = &H12

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

        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()

        Hooked = KeyboardHandle <> 0

    End Function

    Public Sub UnhookKeyboard()

        If (Hooked()) Then
            Call UnhookWindowsHookEx(KeyboardHandle)
        End If

    End Sub

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

        HookKeyboard() 'hook system keys
        Me.TopMost = True 'always on top
End Sub

This "blocked", Alt Tab, Ctrl Esc, the Windows key, but, In Windows XP, it still allowed the task manager to po up once Ctrl Alt Del was pressed. I got around that problem by setting my Form's TopMost property to True, and in a Timer, I added :

    Private Sub frmJolt_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.LostFocus

        Me.Focus() ' when form object loses focus (another form, control, or program - form always has focus)

    End Sub

    Private Sub tJolt_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tJolt.Tick

        Me.BringToFront() 'top in zorder, other apps move to the back

    End Sub

What this did was when the Task Manager popped up, I immediately return focus to my application, only once the application has ended, I could see the Task Manager

The basic idea of the program was to block people from accessing my pc. i set the BorderStyle to None, and used an Easter egg ( a secret key and mouse click combination ) to show my user name and Password boxes. If the correct Username and password have been entered, the application exits, if not, it will allow three tries, whichafter the system will reboot

What I'm trying to say is that, you can hide the Task Manager this way, if you don't want to write your own gina.dll

Some virus scanners, such as AVG ( which I use ), will see your gina.dll as a huge threat and most likely remove it, keep that in mind as well.

Another "bad" option, is to disable the display of the Task Manager through the registry, but I'm not going to eloborate on that. The Task Manager is there for a reason.

[d_rev]

You can download a ginastub from Microsoft in a Platform SDK. There is an example but it's not complete.

You could have my code, if I only knew where to send it .

Dear HenrikLaholm, can I have your internet kiosk code to disable ctrl-alt-del, alt-tab, alt -f4, windows key. I really need that in order to accomplish my project. The time period
given for my project is almost finish. I hope that you can send it as soon as possible. Thanks.

Btw, can I have your messenger name? so I can easily contact you later....

[HanneSThEGreaT]

Concerning your PM

Dear HanneSThEGreaT, I've tried the code you give me. The code can run, but it only can handle The alt+tab key. And it has weakness, That is , if you run it in vista. AND when you press the alt+tab and the choosen window is show desktop, it will show the desktop. Can you help me handle this problem and how to disable ctrl-alt-del and enable it again. You can send any related codes in vb.net 2008 to my email address.

One more thing, can you help me to contact HenrikLaholm. and tell him to please send the code of his internet kiosk software to my email address

I've tried to contact him. But, he disable the PM function, so I can't contact him. The time for me to finish this software is only left one until two weeks, so please help me do it as soon as possible.

Thanks for your help....

First, I do not offer help through PMs or Emails, because it doesn't benefit the community as a whole.
Second, none of us had any idea about what Operating System you are using - with these type of issues, it is absolutely essential to know what OS you are using.
I do not have such an example for Windows Vista, but, I'd recommend you do as suggested by cjard and GremlinSA.
Thirdly, I'm not the right person to speak to about contacting HenrikLaholm.
Lastly, I edited your last post because of the email address - why ¿ Well, to put your email address in a public forum such as this one, you'll end up with endless spam until infinity

[d_rev]

Concerning your PM

First, I do not offer help through PMs or Emails, because it doesn't benefit the community as a whole.
Second, none of us had any idea about what Operating System you are using - with these type of issues, it is absolutely essential to know what OS you are using.
I do not have such an example for Windows Vista, but, I'd recommend you do as suggested by cjard and GremlinSA.
Thirdly, I'm not the right person to speak to about contacting HenrikLaholm.
Lastly, I edited your last post because of the email address - why ¿ Well, to put your email address in a public forum such as this one, you'll end up with endless spam until infinity

Dear HanneSTheGreat, I admit that I'm wrong. I'm sorry for that. I hope that you can edit your post by eliminating my email address. I realize that I've done a fool things. I'll do as what you says. Thanks for guiding me.

[HenrikLaholm]

I have sent you (d_rev) the code by mail, by replying to your mail. I replied to a hotmail address. It could not be sent to the mail address (gmail) you wrote in the mail.

The gina will not work on Vista. In Vista they have another solution.

[keats76]

HenrikLaholm,

Any chance you could shoot me your msgina.dll implementation as well? I'd really appreciate it!

Thanks,
Mike

[dglienna]

You can NOT block c-a-d unless you eliminate GINA.dll, and the only way to do that is to write your own, and replace it.

If someone were to do that, the last thing they'd do is post it on a forum, for the same reason that you don't want your email address posted.

Plus, it would be against the AUP, bypassing the OS.

Why would you have c-a-d on a keyboard anyways? You did say that it was a KIOSK.

Give them an on-screen keyboard, if you have to, or an up/down or joystick.

[FiZiX610]

I'm surprised nobody mentioned this but why not disable it in the registry:

http://www.windowsnetworking.com/kba...XPHomePro.html

[dglienna]

Not XP anymore.

[FiZiX610]

Not XP anymore.

What do you mean? It doesn't work on XP anymore?