To know when OS goes into screen saver

[Rob]

Is there a way that VB can know when the operating system
goes into screen save mode? I have continuous polling I
wish to pause while in screen save mode. And likewise to
wake back up when the screen saver is turned back off.

Any help on this will be greatly appreciated.

Rob

 

[Tom Shelton]

Is there a way that VB can know when the operating system
goes into screen save mode? I have continuous polling I
wish to pause while in screen save mode. And likewise to
wake back up when the screen saver is turned back off.

Any help on this will be greatly appreciated.

Rob

You can use SystemParametersInfo with the SPI_GETSCREENSAVERRUNNING flag
to find out if the screen saver is running... In other words, you could
have a timer that fires every second or so and calls this function. If
it's running put your worker thread to sleep. If it's not, wake it up...

HTH,
Tom Shelton

 

[Fergus Cooney]

Hi Rob,

Certain Windows events can be waited on, eg system shutdown, display
properties changes, etc.(see the SystemEvents class). Unfortunately there's no
mention of any Windows event occurring when the screen saver starts.

The following is a VB (classic) project which detects whether a
workstation is locked or not. It include some very straightforward code to
detect whether the screen saver is running, but you'll have to keep checking.

http://www.mvps.org/st-software/Code/DetectLockedWorkstation.zip

Regards,
Fergus

 

[Armin Zingler]

Is there a way that VB can know when the operating system
goes into screen save mode? I have continuous polling I
wish to pause while in screen save mode. And likewise to
wake back up when the screen saver is turned back off.

Any help on this will be greatly appreciated.

Protected Overrides Sub WndProc( _
ByRef m As System.Windows.Forms.Message)

Const WM_SYSCOMMAND As Integer = &H112
Const SC_SCREENSAVE As Integer = &HF140

MyBase.WndProc(m)

If m.Msg = WM_SYSCOMMAND _
AndAlso m.WParam.ToInt32 = SC_SCREENSAVE Then

Debug.WriteLine("Screensaver activated")
End If
End Sub

 

[Rob]

Thank you Fergus, I look at the example.

Rob

 

[Tom Shelton]

Protected Overrides Sub WndProc( _
ByRef m As System.Windows.Forms.Message)

Const WM_SYSCOMMAND As Integer = &H112
Const SC_SCREENSAVE As Integer = &HF140

MyBase.WndProc(m)

If m.Msg = WM_SYSCOMMAND _
AndAlso m.WParam.ToInt32 = SC_SCREENSAVE Then

Debug.WriteLine("Screensaver activated")
End If
End Sub

Well, I'll be... You learn something new every day. That is going down
in my little book of knowledge...

Tom Shelton

 

[Rob]

Thank you Armin. That looks very straight forward. Is
there a listing anywhere of these great little Windows
Message constants?

Rob

 

[Armin Zingler]

Well, I'll be... You learn something new every day. That is going
down in my little book of knowledge...

Unfortunately, I don't know how to detect when the screen saver is closed.

 

[Armin Zingler]

Thank you Armin. That looks very straight forward. Is
there a listing anywhere of these great little Windows
Message constants?

Press <F1> and select "MSDN library". ;-)


In this case, I added
Debug.WriteLine(m)
to Sub WndProc, waited for the screen saver to be started and found out that
WM_SYSCOMMAND is sent. In the help index, after pasting "WM_SYSCOMMAND" you
get the message documentation.

 

[Tom Shelton]

Unfortunately, I don't know how to detect when the screen saver is closed.

Well, then... I guess that does put a damper on things Using the
SystemParametersInfo - you can find out...

Tom Shelton

 

[Tom Spink]

Write a DLL that injects itself into the CreateProcess API and detect which
process is created when the screensaver comes active... Then, wait until the
process has terminated and therefore the screen saver has closed.

--
HTH,
-- Tom Spink, Über Geek

Please respond to the newsgroup,
so all can benefit

"Chaos, Panic, Disorder, my work here is done"


: > > Protected Overrides Sub WndProc( _
: > > ByRef m As System.Windows.Forms.Message)
: > >
: > > Const WM_SYSCOMMAND As Integer = &H112
: > > Const SC_SCREENSAVE As Integer = &HF140
: > >
: > > MyBase.WndProc(m)
: > >
: > > If m.Msg = WM_SYSCOMMAND _
: > > AndAlso m.WParam.ToInt32 = SC_SCREENSAVE Then
: > >
: > > Debug.WriteLine("Screensaver activated")
: > > End If
: > > End Sub
: > >
: > >
: >
: > Well, I'll be... You learn something new every day. That is going
: > down in my little book of knowledge...
:
:
:
: Unfortunately, I don't know how to detect when the screen saver is closed.
:
:
:
: --
: Armin
:

 

[Herfried K. Wagner [MVP]]

Hello,

Is there a way that VB can know when the operating system
goes into screen save mode? I have continuous polling I
wish to pause while in screen save mode. And likewise to
wake back up when the screen saver is turned back off.

http://www.mvps.org/dotnet/dotnet/samples/operatingsystem/index.html
-> "ScreensaverStart"

 

[Chris Dunaway]

Press <F1> and select "MSDN library". ;-)

In addition, I found the following link very useful...

http://www.codeproject.com/csharp/Win32.asp?df=100


Chris