I'm trying to trigger a desktop slideshow change but I can't find a public API to do it...
The closer I got was to see the name of the methods that are using (they are using a COM object, but I don't know the CLSID to instantiate it).
I already know how to change the desktop wallpaper (i'm doing that already), what I want is a way to trigger the slideshow transition (new to Windows 7).
This doesn't answer your question, and you may have worked it out already, but if the desktop slideshow engine (as I'll call it) has been started (if you bring up 'Personalize' > 'Desktop Background' then choose 'Windows Desktop Backgrounds' from the 'Picture location' drop down, then you'll see the background fade in and out - that's the engine on) then you can use the IActiveDesktop interface by calling 'SetWallpaper' with your JPEG picture and then 'ApplyChanges' with the following parameters:
AD_APPLY_ALL | AD_APPLY_FORCE | AD_APPLY_BUFFERED_REFRESH
When you do you'll notice the slideshow transition effect is used to show the wallpaper you've specified. Lovely.
Reboot however (or kill off Explorer.exe and re-start it) and the same call won't do the transition, it'll just change the background in the old, instant way. Some digging with Spy++ shows that when the slideshow engine is running, the actual desktop FolderView no longer lives under 'Program Manager' in the window parent / child relationship, it's owned by a new window called 'WorkerW' which lives inside Explorer (ties up nicely with your call stack above). In other words, it's taking control of the desktop window from Progman.
So what you need to do is figure out how to get Explorer to initialise that new owner of the desktop window (the 'slideshow engine') and then you can use the IActiveDesktop interface to change the background.
Related
I am a noob when it comes to Desktop GUIs. Is there a way for me to programmitically figure out which application window is the top most in terms of display environment?
So, basically, I can have a process running in the background, that might then change the behavior of the top-most (or say the selected) window. My go to operating system would be MacOS (then Linux family). Also, for instance, there is an app called spectacle app, which listens to key bindings to snap resize and move active windows on MacOS.
I have a VB6 executable we use as a Starter executable for our real program.
The problem is that windows 7 shows a new icon in the taskbar for the new process, instead of the one i clicked on to start my program (of course, because the starter exe has already ended, and the new exe seems to be a new program).
Currently I use the Shell object to start the other exe. Is there a better way to do it from vb6, maybe by using a native C function with declare that does start an exe in the current process, without spawning a new process?
EDIT:
Thanks to atzz for the great information about Application Model IDs. I now have a shortcut to my app starter with a well defined id, and my app also sets the ID when started, and is now accesssible beautifully from the right icon in the toolbar. However, two problems persist:
The app is a Java App started with Exe4J, and I don't have any chance to set the AppID before Exe4J shows the splash screen, so while showing the splash screen there is a second icon in the taskbar.
If I don't manually drag my starter app icon from the Desktop to the toolbar, but instead use my apps icon and set it to be "sticky", the real app is sticked, and not the launcher.
Both problems would be beautifully solved if my launcher would start the app from within its own process. I heard something of using exec() instead of fork() for linux programs to achive this... is there something similar for windows?
I believe there is a way to accomplish what you need via Windows 7 taskbar API, though I never did it myself and thus don't remember clearly enough what I've read on the subject. Look around the Application ID concept.
Some links:
Developing for the Windows 7 Taskbar – Application ID
Inside Windows 7 - Introducing The Taskbar APIs
If the problem is the icon, why not give both programs the same icon (and the same App.Title). Then the user won't be able to tell the difference between the two taskbar entries. Presumably they aren't both visible at the same time.
Alternatively set your starter app not to appear in the taskbar (Form property ShowInTaskbar = False in the design view)
I am trying to write a program that gets the windows that are displayed on the screen. Something like screen.getActiveWindow().size would be cool, but it only addresses the active window.
I am looking for the sizes of all windows on the screen, as well as event information when they are resized, cover each other up.
Am I just daydreaming or is there a way to get this information on windows?
You need to use EnumWindow Function go get the hwnd of each window then user EnumChildWindow to get the child windows and finally get windowinfo the clr doesn't have all of the necessary function to do low level window manipulation unless its been added in 4.0 and I haven't noticed.
I have a hidden process that waits for non-standard hardware button messages and runs an application (with CreateProcess). No problem with the user disturbing, it's an action that the user approved himself. Everything is fine when it's usual layout with taskbar shown and multiply captioned and non captioned- windows. But the situation is different in XP and 7, when the current application is full-screen. Full-screen application in this case is window without borders having exactly the same dimension as the screen. Windows hides taskbar for such application even if it's always on.
In Xp, it's ok, the taskbar is being shown in this case and appication (for example calculator) also, the full-screen app is still visible in areas other than the launched app's and taskbar'. But in Windows 7 nothing visual happens, the full-screen app is still on and if I switch to taskbar, the executed application is there. I tried to solve it with SetForegroundWindow, BringWindowToTop, even AllowSetForegroundWindow(GetCurrentProcessId()) call for a window handle found with CreateProcess-WaitForIntputIdle-EnumThreadWindows, no change. So did something change since XP related to full-screen windows that officially documented?
Thanks,
Max
I would imagine that, if you have your own hardware device, that there is some API for generating "real" user input. Clearly the legacy keyboard and mouse, and now USB HID drivers (many of which are usermode I think?) have access to an API to do so.
Synergy+ for example can generate fake keyboard and mouse events on connected PCs, and the consequence of the faked input is windows switching activation normally.
So, my initial idea is for your usermode "Device" application to synthesize actual keyboard messages - SendInput seems a likely candidate for "the API that can "fake" real user input events.
Then, use an API like RegisterHotKey in your "UI" app to respond to the hotkey combination your device app generates.
Now, (assuming that SendInput IS generating user input events at the correct level), you should (from within the WM_HOTKEY handler in your UI app) have permission (because everything was "user initiated") to change the foreground window (to yourself).
Vista introduced the desktop composition feature. In short, all windows are drawing to a memory bitmaps and the Desktop Window Manager is then composing these bitmaps and drawing on a full-screen Direct3D surface. Full-screen windows do not participate in the desktop composition and get to draw directly on the screen (mostly because the majority of full-screen apps are games that need real-time screen updates).
In particular, this means that when a full screen app is up and running, it is covering the DWM composed image and the user needs to switch to a DWM-managed window for the DWM to start drawing on top of the full-screen app.
I don't have a good solution for your problem, unfortunately. One way to solve it would be to add the WS_CAPTION style to your app and then handle WM_NCPAINT/WM_NCCALCSIZE/WM_NCHITTEST yourself. This would allow you to lie to the DWM that you are a regular windowed application, but change visually your NC area to look like you have no title. However, this does require certain amount of additional code and might be a bit more effort you want to invest.
Another way you can try to solve your problem is to explicitly minimize your full-screen application window when launching the new process. However, you will then have to solve the problem of when to maximize it back again.
Btw, you might find the comments on this post from Raymond Chen interesting.
Windows supports multiple desktops and my guess would be that the full screen up is using a different desktop than the default one (where your application will be shown). A desktop object in Windows is "a logical display surface and contains user interface objects such as windows, menus, and hooks". For example, screen savers normally are started on a separate desktop.
You can find out which desktop an application is running on using Process Explorer:
Set Process Explorer to replace Task Manager and to run always on top.
When your full screen up is shown, launch Process Explorer by pressing Ctrl + Shift + Esc
Within Process Explorer, select the full screen process and press Ctrl + H to display the handles of this process
See the value of the Desktop item in the list. Usually this would be set to Default
If you know what desktop this app is running on you can start your process on the same desktop by first calling OpenDesktop to get a handle to this desktop and then pass it into the STARTUPINFO of your CreateProcess call.
I have an application that manages patient demographic information. Along with this data a user can scan a picture of a patient and assign that picture to a patient. When the user clicks the scan button a separate application is opened as a dialog in order to scan the image. When running this on XP everything worked fine. The imaging application loaded up fine and gained focus. On Vista however occasionally the imaging application will not gain focus and will popup behind the main application. When running full screen or through 2008 Application Server you cannot see the application, you only get a locked screen and it appears nothing has happened. Is there any way to change the window focus management on Vista to work the way XP did? I'm looking for a way to solve this without making changes to the actual application if possible.
I think you will have to make changes to your application to allow the imaging application to take the focus. I'm going to assume that your application launches the imaging application through ShellExecute or CreateProcess. If so, you can get the process handle of the launched process either through SHELLEXECUTEINFO.hProcess (for ShellExecute) or PROCESS_INFORMATION.hProcess (for CreateProcess). Immediately after launching the imaging application call the AllowSetForegroundWindow API:
AllowSetForegroundWindow(GetProcessId(hProcess));
This will allow the imaging application to place its main window/dialog in the foreground when it's starting up.
You could try the following steps:
1. Right Click on the exe
2. Select Properties
3. Select the Compatibility Tab
4. Check the Run this program in campatibility mode for:
5. Select Windows XP (Service Pack 2)
You could iterate through all top level HWNDs and identify the scanning application via its window class, then send an appropriate message to raise the window.
I don't believe this is Vista vs XP related. I think that simply this imaging app takes longer to start on Vista.
Since Windows 2000, the window manager has prevented background applications stealing the foreground. When an application is launched, it has a window of opportunity to create and show a window that will take the foreground. If it takes too long, the window manager thinks that the current window should keep the foreground, and inhibits the other app taking the foreground when it does finally launch.
I can't think of any specific way to avoid this... other than using FindWindow to search for the other apps window after launching the app. When you eventually find it, call SetForegroundWindow on it to bring it to the foreground.