In my WPF application, I have multiple classes each of which implements a message loop. All of these message loops then run in parallel when I create objects of these classes. These objects may show a dialog box at times. The main application thread must keep an eye on these objects and make sure none of them is stuck with the dialog (and press Cancel (Escape key) if it determines such cases). What is the correct way to determine the active foreground window of a thread? I know there is a GetForegroundWindow() API, but it appears as if it works at system level and not thread level.
There's no such thing as the per-thread active foreground window. So what you are explicitly asking for does not have an answer.
Probably the right way to go here, using Win32 at least, is to enumerate top-level windows with EnumWindows. Then use GetWindowThreadProcessId to identify that the window is associated with one of your threads. Finally use GetClassName to identify that the window is a file dialog. Then feel free to do whatever dastardly thing it is you want to do to the window!
On the other hand, this sounds like a perfect candidate for UIAutomation. You are automating testing of UI. UIAutomation will be able to find these file dialog windows and press buttons on them.
Related
I have a WPF-application with multiple unrelated Windows, i.e. there is always one MainWindow and optionally many others with no owner.
If these windows get grouped in the taskbar, windows will provide the action "Close all Windows" in the taskbar context menu.
If it is clicked, each Window of my application gets an individual close-command in an order I cannot control.
Problem:
Some of my windows may ask before closing, if it's okay to cancel pending changes. This is annoying and confusing if there are many of those.
What I want is: If the MainWindow is asked for closing, I want to prompt once, if that's ok. If yes, all windows should close silently, otherwise stay open.
But my MainWindow is not the first one, to process the closing procedure.
I have already found out, that I probably need to check the Windows Message Loop of my MainWindow for some WM_SYSCOMMAND with wparam SC_CLOSE.
(see How can I distinguish between "Close All Windows" and "Close" individual windows in MFC with Windows 7?)
But how can I evaluate this, before I execute the closing-routine for any other window?
ComponentDispatcher.ThreadPreprocessMessage in my mainwindow comes too late, it fires after some other window has started the closing procedure.
This question is somehow related to this one:
Odd form closing behavior when using taskbar's Close All Windows
Personally, I would just leave things as they are. I can see how having several prompts to save/cancel changes could be annoying, but it doesn't seem confusing to me. And while annoying, it seems like a minor annoyance, and frankly one that might teach the user to not use the "Close all windows" option when they have left a bunch of these windows open. That said…
As the question you've found points out, there is no built-in way to distinguish the "Close all windows" from a regular "Close window" command. The system is simply sending the messages to the windows in sequence.
In MFC (i.e. the context of the other question), you can call AfxGetCurrentMessage() to retrieve information about what actually instigated the SC_CLOSE message. If it was user input that was translated to a close command, there will be some type of user input (keyboard, mouse, etc.) as the current message. Otherwise, you'll just see the WM_SYSCOMMAND itself.
But you can't apply the same approach in WPF, because WPF doesn't provide a GetCurrentMessage() method or its equivalent (as far as I know). The only access to window messages you get is to override the Control.WndProc() method, and by the time you get the close command, the most recent window message there will always be the SC_CLOSE.
It seems to me that the best you can do is use the WndProc() override to track incoming messages, so that you can reset a flag when non-close-command messages come in.
Then, when you get the close command and display the user prompt, you can check that flag. If it's set true, then you can ignore the prompt and just use whatever the user most recently selected. Since you're clearing the flag any time non-close-command messages come in, the first close command received will always display the prompt.
Another alternative would be pre-emptively close all the remaining windows. Here you'd still have the prompt have some kind of "apply to all other windows" option for the user, but instead of setting of just relying on the flag, you could actually close all the other windows explicitly.
Neither of these are ideal, from a user-interface perspective. The main problem is when the user tries to close just a single window. In the first approach, the user will see the "apply to all other windows" option in the prompt even though there won't be any other windows to close. The second approach is a bit more self-consistent, but adds a feature you may or may not want: the user can close all windows in the program any time they are closing just one window.
Neither of these behaviors are exactly standard Windows user interface behaviors. I.e. in trying to save the user some annoyance (and confusion, though like I said, I don't see that part being the case), you introduce what itself could be potentially confusing to the user.
Given that it involves additional work coding, and may simply exchange one annoying/confusing result for another, the best solution may be simply to not try to address the issue at all.
I want to write some code, that can automatically do actions on active windows.
For example, if i want to press the ignore button once the window that pops if I insert a new DOK.
i thought of a code that once a specific (known) window pops, it presses a few TABs, and presses Enter.
Can I implement such a code? preferrable in C#.
I thought of several answers to your question because it isn't clear what you are asking. One of these topics might be an area for research:
If you want to press keys for the active window in an application other than the one you are running, you might read about elevated privileges, interprocess communication, and accessing the keyboard with Windows function calls. You can not normally do anything to other applications other than to cause Windows to send it various messages. Thought: how will you indicate when the press the keys if your application is not the active window?
If the active window is one within your application, then you will be better off in the long run by finding a solution that fits C#'s object-oriented model. If you want certain code to be run at times for certain windows (when one is active), you can share code by putting it into a common superclass and having your window classes inherit it. Looking at it this way will be instructive, but you may have to find a somewhat different solution, since it sounds like your window should be inheriting Window's Window class (you can only have one parent class in C#). You could look up "class inheritance" and perhaps "interfaces."
Another solution that isn't so object-oriented for sharing code is to put it into a static function and call this function as needed in the code of your active windows. But ideally, it is code in the active window class that should be manipulating the window. You can put it into a function and then call the function from anywhere in the application that has the "this" reference for the active window.
I'm currently using a delegate to poll the current active control from the currently focused external form every few milliseconds, which works badly.
The title of the question is somewhat confusing, as this does not actually have anything to do with Application.OpenForms. That property just exposes a collection of all the currently open forms. If a new form is opened that had not previously been opened, it will be added to the collection. But the operating system allows only one active window at a time on the desktop, so what you really want is to get notified when the active window changes. Polling will work for this, but it isn't a good solution.
You will either need to install a global hook (WH_CBT is likely the one you want), or take advantage of the WinEvents infrastructure (via the SetWinEventHook function) intended for accessibility tools. Both of these will provide you with a notification when the active window changes. Of course, their scope won't be limited to the application that you are testing. You'll get notification when the active window on the desktop changes to any other window. It will be up to you to filter that down to the application you care about.
I don't have time at the moment to translate any of the required code to C#/.NET, but you can probably find it somewhere online, once you know what to search for. Additionally, WinEvents is already wrapped for you in the System.Windows.Automation namespace.
I need help handling minimized programs when using a custom/self made explorer.exe file .. because unless properly handled, minimized programs will just shrink to something like 100x50px and stay on screen. I worked out a Timer in C# to check for "iconic" processes, list their mainWindowHandler, and move them outside the screen with "MoveWindow". To bring them back I use the handler and the "ShowWindow" function wich works AWESOME .. but as I said, it involves a constantly running Timer, so there must be a cleaner/easier way of achieving this.
Any ideas? Some way to hook and raise an event when a window is minimized?
*please note: show and movewindow are functions from user32.dll. I'm not trying to catch when MY forms are minimized, but when the OTHERS programs are.
You can create a hook to check when windows are being minimized.
I found a CodeProject article that uses hooks to check when the user opens a system menu (ALT+SPACE) on any window, and then appends an extra item to it. You can use that code to check when the user hits the minimize button, and run whatever code you need there.
The CodeProject article is written in C++, but you can adapt the same method for C# (or use P/Invoke).
I have a windows form application which needs to be the TopMost. I've set my form to be the TopMost and my application works as I'd like it to except for in one case.
There is a 3rd party application (referred to as player.exe) that displays SWF movie files on a portion of the screen that popup on top of my application.
Using Process Monitor I determined that player.exe application calls
flash.exe <PositionX> <PositionY> <Width> <Height> <MovieFile>
in my case:
flash.exe 901 96 379 261 somemovie.swf
Since flash.exe is being spawned in a new process after my form has been set to the TopMost it is appearing on top of my application.
First thing I did was make my application minimize the player.exe main application window hoping that this would prevent the Flash from appearing also. But, unfortunately it doesn't... even with the window minimized whenever the flash movie starts it shows up at the pixel location (901,96). I then tried creating a timer to keep setting the form.TopMost property to true every 10ms. This sort of works but you still see a very quick blip of the swf file.
Is there some type of Windows API call which can be used to temporarily prevent player.exe from spawning child processes which are visible? I admit it sounds a little far fetched. But, curious if anyone else has had a similar problem.
Addendum:
This addendum is to provide a reply to some of the suggestions layed out in Mathew's post below.
For the emergency situation described in the comments, I would look at possible solutions along these lines:
1) How does the third party application normally get started and
stopped? Am I permitted to close it
the same way? If it is a service, the
Service Control Manager can stop it.
If it is a regular application,
sending an escape keystroke (with
SendInput() perhaps) or WM_CLOSE
message to its main window may work.
Easiest way to close the app is to CTRL-ALT-DEL, then kill process. -OR-
The proper way is to Hold ESC while clicking the left mouse button... then input your username and password, navigate some menu's to stop the player.
There is no PAUSE command... believe it or not.
I don't think using WM_CLOSE will help since minimizing the application doesn't. Would that kill the process also? If not, how do you reopen it.
2) If I can't close it nicely, am I permitted to kill it? If so,
TerminateProcess() should work.
I can't kill the process for two reasons. 1) Upon relaunch you need to supply username/password credentials... There may be a way to get around this since it doesn't prompt when the machine is rebooted but... 2) Whenever I kill the process in task manager it doesn't die gracefully and asks if you want to send an error report.
3) If I absolutely have to leave the other process running, I would try
to see if I can programmatically
invoke fast user switching to take me
to a different session (in which there
will be no competing topmost windows).
I don't know where in the API to start
with this one. (Peter Ruderman
suggests SwitchDesktop() for this
purpose in his answer.)
I got really excited by this idea... I found this article on CodeProject which provides a lot of the API Wrapper methods. I stopped implementing it because I think that in order for desktop's to work you must have explorer.exe running (which I do not).
EDIT2: On second thought... maybe explorer.exe isn't needed. I'll give it a try and report back.
Edit3: Was unable to get the code in that article working. Will have to put this on hold for a moment.
Answer Summary
As one might have expected, there is no simple answer to this problem. The best solution would be to problematically switch to a different desktop when you need to guarantee nothing will appear over it. I was unable to find a simple C# implementation of desktop switching that worked and I had a looming doubt that I would just be opening a whole new set of worms once it was implemented. Therefore, I decided not to implement the desktop switching. I did find a C++ Implementation that works well. Please post working C# virtual desktop implementations for others.
Setting the TopMost property (or adding the WS_EX_TOPMOST style to a window) does not make it unique in the system. Any number of topmost windows may be created by any number of applications; the only guarantee is that all topmost windows will be drawn 'above' all non-topmost windows. If there are two or more topmost windows, the Z-order still applies. From your description, I suspect that flash.exe is also creating a topmost window.
Aside from periodically forcing your window to the top of the Z-order, I think there is little you can do. Be warned, however, that this approach is dangerous: if two or more windows are simultaneously trying to force themselves to the top of the Z-order, the result will be a flickering mess that the user will likely have to use the task manager to escape.
I recommend that your program not attempt to meddle with other processes on the computer (unless that is its explicit purpose, e.g. a task manager clone). The computer belongs to the user, and he may not value your program more highly than all others.
Addendum:
For the emergency situation described in the comments, I would look at possible solutions along these lines:
How does the third party application normally get started and stopped? Am I permitted to close it the same way? If it is a service, the Service Control Manager can stop it. If it is a regular application, sending an escape keystroke (with SendInput() perhaps) or WM_CLOSE message to its main window may work.
If I can't close it nicely, am I permitted to kill it? If so, TerminateProcess() should work.
If I absolutely have to leave the other process running, I would try to see if I can programmatically invoke fast user switching to take me to a different session (in which there will be no competing topmost windows). I don't know where in the API to start with this one. (Peter Ruderman suggests SwitchDesktop() for this purpose in his answer.)
You can use the Process class to start flash.exe directly - and use an appropriate ProcessStartInfo settings to show the window in a hidden state - or with a WindowStyle of hidden or minimized.
You could also consider using the SetWindowsHookEx API to intercept the process start API calls, and when the process is flash.exe run some code to restore you window to top-most status.
Matthew's answer is excellent, but I suspect you may be asking the wrong question. Why does your application need to be topmost? If you're trying to create a kiosk or some such, then topmost is not the way to go.
Edit: After reading your response to Matthew's comment, I'd suggest creating a new desktop and switching to it before displaying your alert. (See CreateDesktop and SwitchDesktop in MSDN.)