I have written a WinForms driver safety application for a windows tablet device that will blank the screen (display a full screen blank topmost window) when it detects that the car is moving at say more that 15km/h (using the tablets GPS).
The software has worked fine under Windows 7 but I'm struggling a bit to get it working under Windows 8. My first challenge is to display the blank screen when the Metro start menu is currently displayed. So if the user has the Metro start menu displayed and the car starts moving > 15 km/h my blank screen should display... I need to steal the focus from the metro interface and display my blank window on the desktop.
To test this I wrote a simple vb.net app in 2010. It had a form with a timer firing every 3 seconds. In the Tick event I had the code:
Beep()
Me.Activate()
When I ran this with the debugger and pressed the windows key to show the Metro Start Menu, it worked... The focus switched back to the desktop (and my window). However, when I ran this without the debugger and did the same thing I could hear the beeps but the focus never switched back to the desktop.
Any ideas why the behaviour would be different? Any ideas on how I replicate the same behaviour I get when the debugger is attached?
I have tried a few things like AppActivate, setting the form TopMost, BringToFront but unfortunately this hasn't worked.
The only half solution I have come up with is to send a windows button keystroke but this has other issues.
Windows specifically tries to prevent applications from stealing the foreground from other apps. See the SetForegroundWindow documentation for commentary on this and the factors that can let an application come to the foreground (all of the methods you are trying essentially come down to a SetForegroundWindow call).
Note that one of the explicit blocking circumstances is "The foreground process is not a Modern Application or the Start Screen."
This works for you when debugging because "The process is being debugged" is one of the cases which explicitly allows foreground privileges.
Because this is a generally user-unfriendly thing to do there isn't a good general purpose way to bypass this behaviour and steal the foreground.
Likewise, normal apps cannot run on top of Modern applications or the start screen.
You may be better off locking the system by calling the LockWorkStation function.
Related
TL;DR Can I make a VB.net form visible on the Windows lock screen [i.e. when a user hits WIN+L]?
I wrote an alert system that notifies staff of a 'lockdown' in vb.net. This has been tested in drills a few times but today it was noted that the 'alert window' does not appear when the screen is locked.
The alert window does make an alarm sound, which can still be heard even when the computer is locked but this is dependant on the machine having speakers that are turned on...
The workstations are running Windows 7.
Edit
I am not looking to spawn a separate process, just get the 'lockdown.vb' form showing on top of the windows lock screen.
Googling this has just given me a load of tutorials on making a lockscreen...which is not what I'm after, hence the question. :-)
I have a Winforms app with a main form where a multiline text box is updated during a long running process.
I would like to be able to use the ALT-TAB facility of Windows to switch away from the Visual Studio 2012 IDE to watch the form being updated as the app runs.
Is there some option that controls this? If I have other apps running such as Notepad I can toggle away from the IDE but navigating in this way to the running Winforms app seems to be disabled.
Last time I debugged an app like this I recall this sort of switching worked but sometimes there was a lag in the rendering of the screen.
The winforms app is not multithreaded.
Any ideas?
The winforms app is not multithreaded.
Which means you're doing all your lengthy processing on the UI thread. And that, in turn, means that during that processing, your app is ignoring all the messages Windows is sending it, like the "hey, somebody just Alt+Tabbed to you, so bring yourself to the front" message.
You either need to sprinkle your code with frequent calls to Application.DoEvents (not recommended, but could work if you don't intend to maintain this app long-term), or move your long-running logic into a background thread so your UI thread can stay responsive to messages.
I am making a vim-style "window manager" that takes text input, much like Alfred or Spotlight in Mavericks (in a floating panel).
The problem I'm having is when I call activateWithOptions: on a running application it steals focus from my window. I was hoping the problem would be solved by simply bring my app to the foreground again, however it seems the activation is running on a separate thread, and I end up activating my app before the original app gets activated.
I have tried reactivating when I receive NSWorkspaceDidActivateApplicationNotification, but that doesn't work either.
Ideally I'd like to pause execution until the application is focused for multiple reasons, since that would be the window I manipulate further.
Does anyone have any suggestions?
I have a chat application written in VB.net which is used to chat between users who are connected in LAN inside a office . The application popups whenever user gets new chat message. It works fine in windows XP. But sometimes in windows 8 the application fails to popup the chat window. So my chat window is not appearing at the top when popup occurs for new messages.
I have tried using setwindowspos, form.Show(), form.BringToFront() which can bring the form to topmost. But sometimes this will not work properly.
So is there any other method other than those three(which i have mentioned above) i have used which can make the form popup and bring it to front.
Your WinForms app is a desktop application, so it's likely that the reason the pop-up is not being displayed in Windows 8 is because the desktop is not visible.
Remember that Windows 8 brings with it a whole new Start Screen interface and relegates the desktop to an alternate mode. All desktop applications still run, but they run in this separate mode and cannot interact with the new Metro applications (or whatever they're calling them nowadays). Yes, it's too bad that the usability folks at Microsoft didn't listen to Larry Tesler and have decided instead to mode us in, but c'est la vie.
So anyway, the pop-up is still being displayed, but it's being displayed on the desktop, which is not visible. Bringing it to the top isn't doing any good because it's already at the top of all the other windows on the desktop. If you click on the "Desktop" tile in the Start Screen, you should see your window.
Fixing this problem is going to take some work. Forcing a focus switch to the desktop mode is a horrible idea from a usability perspective, and I'm not sure it's even possible. A better solution would be to look into using Toast notifications instead, which can be done from a desktop application.
VS2012's default C# "Metro style" project templates include code in App.xaml.cs (in the OnLaunched override) to restore the application state after a suspend-and-terminate. This code only runs when LaunchActivatedEventArgs.PreviousExecutionState is Terminated, i.e., "The app was terminated after being suspended."
How can I force my app to be suspended and terminated, so I can test this suspend/resume functionality in my app?
Things I've tried that don't work:
If I use the "close app" gesture (drag from the top of the screen to the bottom), then the next run's PreviousExecutionState is ClosedByUser.
If I kill the app -- either using Task Manager, or (if I was debugging) with the "stop" button on the VS toolbar -- then the next run's PreviousExecutionState is NotRunning. This is true even if Task Manager showed the app as "Suspended" before I ended task, so clearly it's more nuanced than the description of "terminated after being suspended".
You'd think I could just switch away from my app, and then open lots of other Metro-style apps until my app eventually gets kicked out. But even if I open every single Metro-style app that ships with the Windows 8 Release Preview, that's apparently not enough memory pressure to make Windows terminate my app. (I assume Windows would be less likely to terminate an app that was being debugged, so I launched my app from the Start screen -- no debugger -- before I tried this.)
It does appear that, if I switch away from my app and type into a StackOverflow window for several minutes, that my app will eventually get terminated, so perhaps there's a time-based component to it. But if I have to wait five or ten minutes every time for my app to terminate, that's a pretty slow testing cycle.
Given that this is something developers will have to test, you'd think there would be a nice, easy way for a dev to force an app to suspend-and-terminate. Is there some kind of stress-test app that comes with Visual Studio that will force enough memory pressure? Is there some menu item in Visual Studio that will force termination of my app? How are we supposed to test this?
In Visual Studio 2012, when you're debugging, there are "Suspend", "Resume" and "Suspend and Shutdown" buttons. By default, you should see the buttons while you are debugging your app. See this article for more info on debugging process lifecycle.
I had trouble finding the Suspend control because VS wasn't showing a second row of toolbars for me. As it turns out, this is on the "Debug Location" toolbar. Make sure you have this toolbar turned on and then you should be able to find the Suspend control (and it does work to solve the OP's problem).
If they don't show by default, go to TOOLS -> CUSTOMIZE, and under the Toolbars tab, check the box that says "Debug Location"
I was looking for VS 2013, just in case others came for the same reason.
Source:
http://blogs.msdn.com/b/visualstudio/archive/2012/08/23/new-visual-studio-2012-debugging-features-for-the-windows-8-app-lifecycle-model.aspx
a busy cat http://blogs.msdn.com/cfs-file.ashx/__key/communityserver-blogs-components-weblogfiles/00-00-01-29-92-metablogapi/2210.image_5F00_thumb_5F00_1FBA9C1E.png