How can I lock an application after period of user inactivity?

My post on StackOverFlow.com

I have a fat Windows application written in VB6. User must log into the application to use it. I need to log the user out after a period of inactivity. There are over 100 separate forms with one Main form that is always open after the user logs in, so I am looking for an application solution not a form level solution.

Here is the solution I decided upon. I wanted to document it properly. As this is the approach I had envisioned, it is not my code. Someone smarter than I did awhile ago.
I simply implemented the solution into my application.

The app is an multiple-document interface app.

Private Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hHook As Long) As Long
Private Declare Function CallNextHookEx Lib "user32" (ByVal hHook As Long, ByVal nCode As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (pDest As Any, pSource As Any, ByVal cb As Long)
Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Long) As Integer

Private m_hDllKbdHook As Long

Private Type POINTAPI
x As Long
y As Long
End Type
Private Declare Function GetCursorPos Lib "user32.dll" (ByRef lpPoint As POINTAPI) As Long


Global variables to hold DateTime last user activity and if mouse and keyboard activity has occurred

Public KeysHaveBeenPressed As Boolean
Public HasMouseMoved As Boolean
Public gLastUserActivity As Date

Code to detect keyboard activity

Public Function HookKeyboard() As Long
On Error GoTo ErrorHookKeyboard
m_hDllKbdHook = SetWindowsHookEx(WH_KEYBOARD_LL, AddressOf LowLevelKeyboardProc, App.hInstance, 0&)
HookKeyboard = m_hDllKbdHook
Exit Function
ErrorHookKeyboard:
MsgBox Err & ":Error in call to HookKeyboard()." _
& vbCrLf & vbCrLf & "Error Description: " & Err.Description, vbCritical, "Warning"
Exit Function
End Function
Public Sub UnHookKeyboard()
On Error GoTo ErrorUnHookKeyboard
UnhookWindowsHookEx (m_hDllKbdHook)
Exit Sub
ErrorUnHookKeyboard:
MsgBox Err & ":Error in call to UnHookKeyboard()." _
& vbCrLf & vbCrLf & "Error Description: " & Err.Description, vbCritical, "Warning"
Exit Sub
End Sub
Public Function LowLevelKeyboardProc(ByVal nCode As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Static kbdllhs As KBDLLHOOKSTRUCT
If nCode = HC_ACTION Then
'keys have been pressed
KeysHaveBeenPressed = True
End If
LowLevelKeyboardProc = CallNextHookEx(m_hDllKbdHook, nCode, wParam, lParam)
End Function

Code to detect mouse movement:

Public Sub CheckMouse()
On Error GoTo ErrCheckMouse
Dim p As POINTAPI
GetCursorPos p
If p.x <> LastMouse.x Or p.y <> LastMouse.y Then
HasMouseMoved = True
LastMouse.x = p.x
LastMouse.y = p.y
End If
Exit Sub
ErrCheckMouse:
MsgBox Err.Number & ": Error in CheckMouse(). Error Description: " & Err.Description, vbCritical, "Error"
Exit Sub
End Sub



On the Main parent Form:
Added a timer:

Private Sub muTimer_Timer()
CheckMouse
'Debug.Print "MU Timer Fire"
'Debug.Print "Keyboard:" & KeysHaveBeenPressed & " - " & "Mouse:" & HasMouseMoved
If HasMouseMoved = False And KeysHaveBeenPressed = False Then
If DateDiff("m", gLastUserActivity, Now) > gnMUTimeOut Then
muTimer.Interval = 0

Else
'Debug.Print " dT "; DateDiff("s", gLastUserActivity, Now)
End If
Else
HasMouseMoved = False
KeysHaveBeenPressed = False
gLastUserActivity = Now
End If
'Debug.Print " dT "; DateDiff("s", gLastUserActivity, Now)
End Sub

Also on the MainForm load event:

Private Sub MDIForm_Load()
HookKeyboard
end sub

Private Sub MDIForm_QueryUnload(Cancel As Integer, UnloadMode As Integer)
UnHookKeyboard
end sub

Remote Desktop Keystrokes

Remote Desktop Keystrokes

I am not even going to pretend to memorize these:

Ctrl+Alt+End = Ctrl+Alt+Del (the only truly required one to know!)

ALT+PAGE UP (Switch between programs from left to right)
ALT+PAGE DOWN (Switch between programs from right to left)
ALT+INSERT (Cycle through the programs in most recently used order)
ALT+HOME (Display the Start menu)
CTRL+ALT+BREAK (Switch the client computer between a window and a full screen)
ALT+DELETE (Display the Windows menu)
CTRL+ALT+Minus sign (-) (Place a snapshot of the entire client window area on the Terminal server clipboard and provide the same functionality as pressing ALT+PRINT SCREEN on a local computer.)
CTRL+ALT+Plus sign (+) (Place a snapshot of the active window in the client on the Terminal server clipboard and provide the same functionality as pressing PRINT SCREEN on a local computer.)

How to create a linked server from a local SQL server instance

I needed to add my local server as a named linked server on my development workstation.
Here is the magic hand shake...

--local linked server
EXEC sp_addlinkedserver
@server='FUSIONRIS',
@srvproduct='',
@provider='SQLNCLI',
@datasrc=''

Resolving CAPICOM reference for .net project

The following was taken from : http://www.jensign.com/JavaScience/CapiCert/index.html

CAPICOM 2 Interop:
Much of the useful certificate store functionality of cryptoAPI has been encapsulated in CAPICOM. CAPICOM provides advanced capability, including support for pkcs7 signatures, envelopes, encryption, Authenticode signatures and advanced certificate store access. CAPICOM requires an end user component dll installation and registration, and deployment of a .net interop assembly. An interop assembly for CAPICOM can be easily built using:

tlbimp capicom.dll /namespace:CAPICOM /out:Interop.CAPICOM.dll

This is essentially the same command executed by VS.net when the COM reference is added. Note that the interop assembly has explicitly been given the namespace CAPICOM while the assembly is titledInterop.CAPICOM. The simple C# application below is compiled using:

csc /r:interop.capicom.dll FindCertnet.cs

To execute the application, the Interop.CAPICOM.dll assembly must be in the application directory, or if Strong Name signed, can be deployed to the GAC for shared access by other .net applications referencing CAPICOM. The application demonstrates basic certificate store access using CAPICOM. It also demonstrates different ways of using a Certificates enumeration, including the indexer. Casting to the ICertContext interface provides the context that can be used with X509Certificate(IntPtr handle) constructor, although with CAPICOM installed, all the functionality is available from the interop assembly. A few properties of an X509Certificate object are displayed:

Reformatted code examples

When I upgraded by site template, I forgot to re-add div class to format source code.
Code snippet I use is from http://bguide.blogspot.com/

/*
Custom CSS class to display code snippets.
http://bguide.blogspot.com/
2008 Feb 03
*/
.mycode
{
white-space:pre;
font-family:monospace;
font-size:9pt;
line-height: 10pt;
height:auto;
width:auto;
padding:5px;
margin-left:10px;
overflow:auto;
}