Tips dan Trick bagi yang sedang mendalami Visual Basic, ini adalah contoh program agar suatu program tersebut mempunyai fungsi One Tasking (Tidak Multi Tasking).
Disable Alt+Tab di Visual Basic
Langkah Pertama kita harus membuat sebuah modul yang berisi antara lain :
Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Public Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal HWND As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long
Public Declare Function GetKeyState Lib "user32" (ByVal nVirtKey As Long) As Integer
Public Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" (ByVal idHook As Long, ByVal lpfn As Long, ByVal hmod As Long, ByVal dwThreadId As Long) As Long
Public Declare Function CallNextHookEx Lib "user32" (ByVal hHook As Long, ByVal nCode As Long, ByVal wParam As Long, lParam As Any) As Long
Public Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hHook As Long) As Long
Public Const HC_ACTION = 0
Public Const WM_KEYDOWN = &H100
Public Const WM_KEYUP = &H101
Public Const WM_SYSKEYDOWN = &H104
Public Const WM_SYSKEYUP = &H105
Public Const VK_TAB = &H9
Public Const VK_ESCAPE = &H1B
Public Const VK_SHIFT = &H10
'SHIFT key
Public Const VK_CONTROL = &H11
'CTRL key
Public Const VK_MENU = &H12
'ALT key
Public Const VK_LWIN = &H5B
'Left Windows key (Microsoft® Natural® keyboard)
Public Const VK_RWIN =
'Right Windows key (Natural keyboard)
Public Const VK_APPS = &H5D
'Applications key (Natural keyboard)
'VK_LAUNCH_MAIL B4 Windows 2000: Start Mail key
'VK_LAUNCH_MEDIA_SELECT B5 Windows 2000: Select Media key
'VK_LAUNCH_APP1 B6 Windows 2000: Start Application 1 key
'VK_LAUNCH_APP2 B7 Windows 2000: Start Application 2 key
Public Const WH_KEYBOARD_LL = 13
Public Const LLKHF_ALTDOWN = &H20
Public Type KBDLLHOOKSTRUCT
vkCode As Long
scanCode As Long
flags As Long
time As Long
dwExtraInfo As Long
End Type
Dim p As KBDLLHOOKSTRUCT
Public Function LowLevelKeyboardProc(ByVal nCode As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Dim fEatKeystroke As Boolean
If (nCode = HC_ACTION) Then
If wParam = WM_KEYDOWN Or wParam = WM_SYSKEYDOWN Or _
wParam = WM_KEYUP Or wParam = WM_SYSKEYUP Then
CopyMemory p, ByVal lParam, Len(p)
fEatKeystroke = _
p.vkCode = VK_LWIN Or _
p.vkCode = VK_RWIN Or _
p.vkCode = VK_APPS Or _
p.vkCode = VK_CONTROL Or _
p.vkCode = VK_SHIFT Or _
p.vkCode = VK_MENU Or _
((GetKeyState(VK_CONTROL) And &H8000) <> 0) Or _
((p.flags And LLKHF_ALTDOWN) <> 0)
End If
End If
If fEatKeystroke Then
LowLevelKeyboardProc = -1
Else
LowLevelKeyboardProc = CallNextHookEx(0, nCode, wParam, ByVal lParam)
End If
End Function
Langkah Kedua di bagian form kita berikan sebuah CheckBox, dengan uraian sebagai berikut :
Private Sub chkDisable_Click()
If chkDisable = vbChecked Then
hhkLowLevelKybd = SetWindowsHookEx(WH_KEYBOARD_LL, AddressOf _
LowLevelKeyboardProc, App.hInstance, 0)
Else
UnhookWindowsHookEx hhkLowLevelKybd
hhkLowLevelKybd = 0
End If
End Sub
Source Code :
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22/05/2010 10:46 
moestofa 
28259 
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