1. Visual Basic .NET
  2. Screen Lock with IniFile

Screen Lock with IniFile

Submitted by vcarabbacan on Sunday, August 18, 2013 - 18:47.
Language
Visual Basic .NET
This code will allow you to disable alt + f4, ctrl + alt + del, alt + tab, alt + esc, windows key, ctrl + esc. Sample code:
  1. Public Class Form1
  2.  
  3.     Public g_IniSettings As New IniFile
  4.  
  5. #Region "Alt + F4"
  6.  
  7.  
  8.     Protected Overrides ReadOnly Property CreateParams() As CreateParams
  9.         Get
  10.             Dim cp As CreateParams = MyBase.CreateParams
  11.             Const CS_NOCLOSE As Integer = &H200
  12.             cp.ClassStyle = cp.ClassStyle Or CS_NOCLOSE
  13.             Return cp
  14.         End Get
  15.     End Property
  16. #End Region
  17.  
  18.     Friend Sub check_settings()
  19.  
  20.         g_IniSettings.FileName = Application.StartupPath & "\ScreenLockSettings.ini"
  21.  
  22.         Dim fi As New FileInfo(g_IniSettings.FileName)
  23.  
  24.         If Not fi.Exists() Then
  25.             'MessageBox.Show("INI file not found:" & vbCrLf & vbCrLf & g_IniSettings.FileName, "Error")
  26.         End If
  27.  
  28.         Try
  29.             ' Application.Run(New frmSettings)
  30.         Catch e As Exception
  31.             ' MessageBox.Show("Application Error:" & _
  32.             ' vbCrLf & vbCrLf & e.ToString, "Error")
  33.         End Try
  34.     End Sub
  35.  
  36.     Dim terminateProgram As Integer = 0
  37.  
  38.     Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown, TextBox1.KeyDown, Button1.KeyDown
  39.         If e.KeyCode = Keys.Enter Then
  40.             Button1.PerformClick()
  41.         End If
  42.     End Sub
  43.     Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  44.         Timer1.Start()
  45.         check_settings()
  46.  
  47.         g_IniSettings.FileName = Application.StartupPath & "\ScreenLockSettings.ini"
  48.  
  49.         Dim fi As New FileInfo(g_IniSettings.FileName)
  50.  
  51.         If Not fi.Exists Then
  52.             terminateProgram = 1
  53.             TopMost = False
  54.             Form2.Show()
  55.             Me.Hide()
  56.         End If
  57.  
  58.     End Sub
  59.  
  60.     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  61.        
  62.         If TextBox1.Text = g_IniSettings.GetSetting("Role", "Admin") Then
  63.             terminateProgram = 1
  64.             TopMost = False
  65.             Form2.Show()
  66.             Me.Hide()
  67.         ElseIf TextBox1.Text = g_IniSettings.GetSetting("Role", "User") Then
  68.             End
  69.         Else
  70.             terminateProgram = 0
  71.             Timer1.Start()
  72.             TextBox1.BackColor = Color.Red
  73.         End If
  74.     End Sub
  75.  
  76.     Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
  77.         If terminateProgram = 0 Then
  78.             TopMost = True
  79.         End If
  80.     End Sub
  81.  
  82.  
  83. End Class

Note: Due to the size or complexity of this submission, the author has submitted it as a .zip file to shorten your download time. After downloading it, you will need a program like Winzip to decompress it.

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Tags
screen lock

Comments

Submitted by Fawaz Ibrahim (not verified) on Fri, 08/30/2013 - 20:00

I think you can open the file {WINDOWS path + "\system32\taskmgr.exe" } for append and so , if the user press {CTRL + ALT + DEL}, he will have an error message as the following {The current file is being used by another application}

Submitted by edzbil (not verified) on Thu, 09/12/2013 - 16:54

The better way to lock your screen is to kill and start the process so the task manager will be disabled, and start programatically by providing password from a user intend to unlock a computer.