How to create a screen locker in VB.Net(Disable Alt+F4,Alt+Tab,Win Key etc)

In this tutorial we will see how to make a screen locker in vb.net with Alt+ Tab,Alt+ F4,Alt+ Esc,Windows key & Task Manager Disabled .

Steps :

1) Create a new project in visual studio.
2) Select form properties and set FormBorderStyle to None and WindowState to Maximized.
3) Now add a Timer set its interval to 1 & select enabled = true
4) Double click your windows application form.
5) Erase the entire code and paste the code given below

This Code Helps to Disable Alt+F4,ALT+Tab,ALT+ Esc,Win Key & Task Manager :
Imports Microsoft.Win32 Imports System.Diagnostics Imports System.Runtime.InteropServices Public Class Form1 'Structure contain information about low-level keyboard input event Private Structure KBDLLHOOKSTRUCT Public key As Keys Public scanCode As Integer Public flags As Integer Public time As Integer Public extra As IntPtr End Structure 'System level functions to be used for hook and unhook keyboard input Private Delegate Function LowLevelKeyboardProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr <DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _ Private Shared Function SetWindowsHookEx(ByVal id As Integer, ByVal callback As LowLevelKeyboardProc, ByVal hMod As IntPtr, ByVal dwThreadId As UInteger) As IntPtr End Function <DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _ Private Shared Function UnhookWindowsHookEx(ByVal hook As IntPtr) As Boolean End Function <DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _ Private Shared Function CallNextHookEx(ByVal hook As IntPtr, ByVal nCode As Integer, ByVal wp As IntPtr, ByVal lp As IntPtr) As IntPtr End Function <DllImport("kernel32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _ Private Shared Function GetModuleHandle(ByVal name As String) As IntPtr End Function <DllImport("user32.dll", CharSet:=CharSet.Auto)> _ Private Shared Function GetAsyncKeyState(ByVal key As Keys) As Short End Function 'Declaring Global objects Private ptrHook As IntPtr Private objKeyboardProcess As LowLevelKeyboardProc Public Sub New() Dim objCurrentModule As ProcessModule = Process.GetCurrentProcess().MainModule 'Get Current Module objKeyboardProcess = New LowLevelKeyboardProc(AddressOf captureKey) 'Assign callback function each time keyboard process ptrHook = SetWindowsHookEx(13, objKeyboardProcess, GetModuleHandle(objCurrentModule.ModuleName), 0) 'Setting Hook of Keyboard Process for current module ' This call is required by the Windows Form Designer. InitializeComponent() ' Add any initialization after the InitializeComponent() call. End Sub Private Function captureKey(ByVal nCode As Integer, ByVal wp As IntPtr, ByVal lp As IntPtr) As IntPtr If nCode >= 0 Then Dim objKeyInfo As KBDLLHOOKSTRUCT = DirectCast(Marshal.PtrToStructure(lp, GetType(KBDLLHOOKSTRUCT)), KBDLLHOOKSTRUCT) If objKeyInfo.key = Keys.RWin OrElse objKeyInfo.key = Keys.LWin Then ' Disabling Windows keys Return CType(1, IntPtr) End If If objKeyInfo.key = Keys.ControlKey OrElse objKeyInfo.key = Keys.Escape Then ' Disabling Ctrl + Esc keys Return CType(1, IntPtr) End If End If Return CallNextHookEx(ptrHook, nCode, wp, lp) End Function Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean) If disposing AndAlso (components IsNot Nothing) Then components.Dispose() End If If ptrHook <> IntPtr.Zero Then UnhookWindowsHookEx(ptrHook) ptrHook = IntPtr.Zero End If MyBase.Dispose(disposing) End Sub Protected Overrides ReadOnly Property CreateParams As CreateParams Get Dim cp As CreateParams = MyBase.CreateParams Const CS_NOCLOSE As Integer = &H200 cp.ClassStyle = cp.ClassStyle Or CS_NOCLOSE Return cp End Get End Property Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick Me.TopMost = True For Each selProcess As Process In Process.GetProcesses If selProcess.ProcessName = "taskmgr" Then selProcess.Kill() Exit For End If Next End Sub End Class  

6) Now add a label & textbox change its text to "Enter Password" & Login respectively.
7) Now go to Solution Explorer & select My Project
8) In my project select Settings add password in Name Column ,Set its Type as String & value to 1234 as shown below.

9) Now go back to form1 and double click login button & add the following code :
If TextBox1.Text = My.Settings.password Then
Me.Close()
Else
MsgBox("Incorrect Password", MsgBoxStyle.Critical)
End If
10) Save ii & Debug your project.

Note : Use 1234 as your password

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