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I know this question must have been asked hundreds of times before and so, maybe, I'm just doing something wrong. But I have a WinForms program I'm writing to try and keep the system appearing active so as to stop it as registering idle.

I figured that having a Timer on my form and doing something as simple as either moving the mouse via System.Windows.Forms.Cursor.Position or using the SendKeys.Send method would be enough to register user interaction, but it's not registering as user action and still letting the system appear as inactive after a set amount of time.

My code is fairly straightforward... Either:

Private Sub Updater_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Updater.Tick SendKeys.Send("+") End Sub

Or doing something along the lines of:

Private Sub Updater_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Updater.Tick Dim MyMousePosition As Point MyMousePosition = Windows.Forms.Cursor.Position Windows.Forms.Cursor.Position = New Point(MyMousePosition.X - 10, MyMousePosition.Y) End Sub

But neither is doing the trick... How can I get this to work AND preferably in a way that would be of least inconvnience to a user if they are actually using the system? (Meaning that I don't want to send a bunch of keys that may mess up the user if they're actually being active or move the mouse clear across the screen)

I know this coce is in VB, but I'm good with VB / C# solutions.

Thanks!!!

EDIT

As an addition to this question, I used the GetLastInputInfo from the User32.dll to check on the system activity.

Even with my mouse / keyboard events linked to the Timer_Tick event, GetLastInputInfo only gets reset if I physically move the mouse / perform some action on the computer...

I guess my question is What events can I add to my Timer_Tick event that will reset the GetLastInputInfo - In other words, have windows believe the user actually did something on the machine??

Thanks!!!

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    What is your reason for wanting the system not to appear idle? Commented Aug 13, 2013 at 16:13
  • I don't really get what you want. Commented Aug 13, 2013 at 16:15
  • 3
    Possibly use SetThreadExecutionState: stackoverflow.com/questions/6302185/… Commented Aug 13, 2013 at 16:25
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    If that program is using a low-level Windows hook, you're going to have a very difficult time fooling it. You'll have to hook your program in before that program, and send simulated events. No, I don't know how to do that. I suspect that you don't want to try. Commented Aug 13, 2013 at 18:39
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    The documentation for GetLastInputInfo indicates that you can update it by sending information via the SendInput function. Have you tried that? Commented Aug 13, 2013 at 20:19

3 Answers 3

Reset to default
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After a lot of playing around, I came up with a solution that worked and I'm answering this question so as to help anyone out there that may be looking for the same information.

(Coded in VB):

In Declarations Section:

Private Declare Function SendInput Lib "user32.dll" (ByVal nInputs As Integer, ByRef pInputs As INPUT_TYPE, ByVal cbSize As Integer) As Integer Const INPUT_MOUSE = 0 Const MOUSEEVENTF_MOVE = &H1 Public Structure MOUSEINPUT Public dx As Integer Public dy As Integer Public mouseData As Integer Public dwFlags As Integer Public dwtime As Integer Public dwExtraInfo As Integer End Structure Public Structure INPUT_TYPE Public dwType As Integer Public xi As MOUSEINPUT End Structure

The Sub to move the mouse:

Public Sub MoveMouse(ByVal x As Integer, ByVal y As Integer, ByVal flag As Integer) Dim inputEvents As INPUT_TYPE Dim xi As New MOUSEINPUT xi.dx = x xi.dy = y xi.mouseData = 0 xi.dwtime = 0 xi.dwFlags = flag xi.dwExtraInfo = 0 inputEvents.dwType = INPUT_MOUSE inputEvents.xi = xi SendInput(1, inputEvents, Len(inputEvents)) End Sub

The Code in the Timer_Tick Event:

Private Sub Updater_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Updater.Tick ' Move the mouse (relatively) 1 pixel away and then back MoveMouse(1, 1, MOUSEEVENTF_MOVE) MoveMouse(-1, -1, MOUSEEVENTF_MOVE) End Sub

I tested this using the GetLastInputInfo API function and it works!!

... The most helpful link I found was this one: http://homeofcox-cs.blogspot.com/2008/07/c-simulate-mouse-and-keyboard-events.html

Thank you all for all your help and I hope this helps other people too!!

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1 Comment

I used your solution and it works on my laptop well, but it doesn't work on our remote servers, is there any limitation for your solution?
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when we needed the system not to go idle (in WM 6.0 when we ha long logic and the device went idle the logic stopped working) we used

 [DllImport("CoreDll.dll")] public static extern void SystemIdleTimerReset();

it reset the idle timer, not interfering with the user's actions and it worked like charm

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Thanks. Seems about right in terms of the functionality I need, but CoreDll is only for mobile platforms... Any idea at all for desktop???
@JohnBustos look what i have found for you - stackoverflow.com/questions/6302185/…
Thank you so much for finding this.. For whatever reason, you'd think that the ES_SYSTEM_REQUIRED flag would reset the timer (as it says it does), but it doesn't :( ... I'm still stuck on this and it seems the only solution is the SendInput function... If you do know of any others, PLEASE do let me know, though!!!! DARN ANNOYING, but thank you SO much for looking for me....
@JohnBustos i can't find it right now, but i remember that i saw there were some registery values that can be changed to prevent idle state. Can't find it when i need it though
Also a cool idea, but the network setting have those values getting changed back.... NUTS, huh?? - I'm working on the SendInout solution now... I'm still thinking that'll be the most robust....
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There is a much simpler way, that consists in calling the Win32 function:

EXECUTION_STATE WINAPI SetThreadExecutionState( _In_ EXECUTION_STATE esFlags );

with ES_SYSTEM_REQUIRED | ES_CONTINUOUS as argument. Anyway, from this SO issue, it seems that the effect will not persist, even if ES_CONTINUOUS is used. In that case, you should call the function periodically, say every minute, to reset the idle timer. An important thing is that the function only applies to the thread that called it, and its effect terminates when the thread terminates.

When you're done, you should call SetThreadExecutionState(ES_CONTINUOUS) to allow the system to go idle again.

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I tried doing exactly that and it didn't work, but thanks for the information.

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