disable windows, ctrl, alt, del key
CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Page 1 of 2 12 LastLast
Results 1 to 15 of 27

Thread: disable windows, ctrl, alt, del key

  1. #1
    Join Date
    Jun 2008
    Posts
    34

    Question disable windows, ctrl, alt, del key

    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
    Share on Google+

  2. #2
    Join Date
    Oct 2003
    Location
    .NET2.0 / VS2005 Developer
    Posts
    7,104

    Re: disable windows, ctrl, alt, del key

    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
    "it's a fax from your dog, Mr Dansworth. It looks like your cat" - Gary Larson...DW1: Data Walkthroughs 1.1...DW2: Data Walkthroughs 2.0...DDS: The DataSet Designer Surface...ANO: ADO.NET2 Orientation...DAN: Deeper ADO.NET...DNU...PQ
    Share on Google+

  3. #3
    Join Date
    Feb 2006
    Posts
    16

    Re: disable windows, ctrl, alt, del key

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

    Code:
    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
    Share on Google+

  4. #4
    Join Date
    Jun 2005
    Location
    JHB South Africa
    Posts
    3,772

    Re: disable windows, ctrl, alt, del key

    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..
    Articles VB6 : Break the 2G limit - Animation 1, 2 VB.NET : 2005/8 : Moving Images , Animation 1 , 2 , 3 , User Controls
    WPF Articles : 3D Animation 1 , 2 , 3
    Code snips: VB6 Hex Edit, IP Chat, Copy Prot., Crop, Zoom : .NET IP Chat (V4), Adv. ContextMenus, click Hotspot, Scroll Controls
    Find me in ASP.NET., VB6., VB.NET , Writing Articles, My Genealogy, Forum
    All VS.NET: posts refer to VS.NET 2008 (Pro) unless otherwise stated.
    Share on Google+

  5. #5
    Join Date
    Jun 2008
    Posts
    2

    Re: disable windows, ctrl, alt, del key

    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.
    Share on Google+

  6. #6
    Join Date
    Jul 2001
    Location
    Sunny South Africa
    Posts
    11,101

    Re: disable windows, ctrl, alt, del key

    What I did once was to create a keyboard hook, like :
    Code:
    '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 :
    Code:
        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.
    Share on Google+

  7. #7
    Join Date
    Jun 2008
    Posts
    34

    Unhappy Re: disable windows, ctrl, alt, del key

    Quote Originally Posted by HenrikLaholm

    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....
    Last edited by d_rev; July 7th, 2008 at 07:05 AM.
    Share on Google+

  8. #8
    Join Date
    Jul 2001
    Location
    Sunny South Africa
    Posts
    11,101

    Re: disable windows, ctrl, alt, del key

    Concerning your PM
    Quote Originally Posted by d_rev
    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
    Last edited by HanneSThEGreaT; July 7th, 2008 at 07:15 AM.
    Share on Google+

  9. #9
    Join Date
    Jun 2008
    Posts
    34

    Unhappy Re: disable windows, ctrl, alt, del key

    Quote Originally Posted by HanneSThEGreaT
    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.
    Share on Google+

  10. #10
    Join Date
    Jun 2008
    Posts
    2

    Re: disable windows, ctrl, alt, del key

    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.
    Share on Google+

  11. #11
    Join Date
    Mar 2009
    Posts
    1

    Re: disable windows, ctrl, alt, del key

    HenrikLaholm,

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

    Thanks,
    Mike
    Share on Google+

  12. #12
    Join Date
    Jan 2006
    Location
    Chicago, IL
    Posts
    15,002

    Re: disable windows, ctrl, alt, del key

    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.
    David

    CodeGuru Article: Bound Controls are Evil-VB6
    2013 Samples: MS CODE Samples

    CodeGuru Reviewer
    2006 Dell CSP
    2006, 2007 & 2008 MVP Visual Basic
    If your question has been answered satisfactorily, and it has been helpful, then, please, Rate this Post!
    Share on Google+

  13. #13
    Join Date
    Nov 2010
    Posts
    3

    Re: disable windows, ctrl, alt, del key

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

    http://www.windowsnetworking.com/kba...XPHomePro.html
    Share on Google+

  14. #14
    Join Date
    Jan 2006
    Location
    Chicago, IL
    Posts
    15,002

    Re: disable windows, ctrl, alt, del key

    Not XP anymore.
    David

    CodeGuru Article: Bound Controls are Evil-VB6
    2013 Samples: MS CODE Samples

    CodeGuru Reviewer
    2006 Dell CSP
    2006, 2007 & 2008 MVP Visual Basic
    If your question has been answered satisfactorily, and it has been helpful, then, please, Rate this Post!
    Share on Google+

  15. #15
    Join Date
    Nov 2010
    Posts
    3

    Re: disable windows, ctrl, alt, del key

    Quote Originally Posted by dglienna View Post
    Not XP anymore.
    What do you mean? It doesn't work on XP anymore?
    Share on Google+

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


Windows Mobile Development Center


Click Here to Expand Forum to Full Width

This is a CodeGuru survey question.


Featured


HTML5 Development Center