I am developing a windows service, in VB.NET, that launches a legacy application that performs some work. The service acts as a wrapper around the legacy app allowing users to automate an otherwise manual operation.
Everything is working great, except occasionally the legacy app displays a messagebox. When it does this the process halts until the message box is closed.
As the service will be running on a server there will be no user to close the message box.
The service launches the legacy application in a System.Diagnostics.Process.
Is there way to detect that a message box has been displayed by a process that I have started using System.Diagnostics.Process? And is there a way to close the messagebox through code?
I also found that EnumChildWindows does not return the MessageBox. But I found a site that showed me how to do it. http://vbcity.com/forums/t/105842.aspx
You want to call GetWindow passing in GW_ENABLEDPOPUP. It worked like a charm. Thanks to Scott Waletzko!
Use FindWindow to find the app, the use EnumChildWindows to enumerate all it's childwindows until you find the messagebox (if the messagebox isn't a direct child of the main window of the app you might have to have recursive calls I think).
You might be able to skip the FindWindow call and instead use the MainWindowHandle property of the Process, but I haven't checked if that works.
A good tool for looking at all this is Spy++ which can help you see some information you can get hold of about a running process.
Related
Title quite much says it all.
In VB6, and in VBA/Access it was possible to hit break key, and jump into debug mode when using the msgbox() command.
Is there a way to do this in vb.net (desktop/winforms) applications?
Often, some code will toss up a dialog box, and it is rather nice then to jump into debug mode as a result of that message box having been displayed.
Edit
Ok, hitting pause button in most applications work, but in this application, when I hit pause, then I get this:
Edit two:
Ok, I have discovered the reason for this behavior. I have the application Frame work box un-checked. The reason for this is I did't want to specify the main application form as startup form, and I desired additional control over what occurs if the main startup form (that I don't specify) is closed. Thus, my main application form is launched via application.Run(my form)
It thus seems that due to starting the main form as a new separate application thread (which is the result of using application.Run(), then you can't use ctrl-break, or more common use/hit the pause button in the IDE to halt the code. Hitting pause will thus display that the application is running a main app thread, which indeed is the case since I use applicaiton.Run() to launch the main form from the classic and traditional Sub Main().
Edit 3
A way to fix this, and enable the pause key to work is to un-check in tools->debugging the [ ] Enable Just My Code. This will thus allow debug mode of the other "main" application thread.
Hmm. [CTRL][BREAK] clears the dialog box. However, clicking the pause button in the IDE will do what you want.
Alternatively, select Debug > Break All from the menu.
I'm look for code which can help me accomplish what the title suggests.
I want this because I have an issue with a program which is quite buggy (it's a game), and if It freezes, and results in a black screen. Even after using Shift+Ctrl+Esc, Ctrl+Alt+Del, Alt+F4 and the rest of them, I acn't seem to end the program. So I thought that a KeyPress event would work, as it doesn't require me to use the UI in any way.
However, I've never used VB for anything other than Form's, so I have no idea how to start on something which runs in the background.
Thanks :)
A background app won't help in this case.
Ctrl+Alt+Del is specail key combo that is handled directly by Windows and can't be intercepted by a running program.
What this means is that if your game locks up and Ctrl+Alt+Del doesn't bring up the Windows menu, then the game has corrupted the system. The only fix at that point would be a restart.
That being said, you can kill a running process using VB.NET like this:
For Each program As Process In System.Diagnostics.Process.GetProcesses
If program.ProcessName = "ProcessName" Then
program.Kill()
End If
Next
Read more about it on the MSDN.
Okay, so Windows isn't actually locking up, but you just need some way to kill the process. Use the above code, replacing "ProcessName" with the name of your game process, and then either:
(basic) Turn the VB.NET code into an .exe file. Then set up a keyboard macro (using your keyboard software or some freeware) to launch the .exe you made which will kill all running instances of the given process. or...
(advanced) Import "user32.dll" into the VB.NET code, call SetWindowsHookEx with a hook id of 13, a pointer to a LowLevelKeyboardProc function, the handle to your running program, and a thread id of 0. Then, whenever a key is pressed in any program, your KeyboardProc function will be invoked. If the key(s) pressed match your desired kill-key combo, then run the above process killing code. This looks like it may give you more step-by-step instructions.
I am trying to sed a keystroke in vb.net, and my code at the moment is SendKeys.Send("+^(;)")
But unfortunately it won't fire, could anyone tell me why?
I don't recommend using sendkeys for anything really. Reason being that you never can guarantee the keystrokes will go where you intend. This is because you are simulating the input as if it were coming from the keyboard, which also ties up your keyboard.
I suggest instead you take the time and learn about the SendMessage api, or the PostMessage api. With these API's you can send messages to specific windows, regardless of what is going on with the keyboard. For instance, if you write a game bot using sendkeys, then you have to leave your computer alone while it runs and hope no unexpected windows pop open. Whereas if you learn the sendmessage api, then you can write a bot that runs in the background while you do other things with your computer.
here are some links to help:
pinvoke - sendmessage api
pinvoke - postmessage api
A list of windows messages constants/hex values/meanings
A nice description on how to use these api's
Hi ive developed a application that works with my site by using
SendKeys.send("{ENTER}") to submit info on one of my forms.
Is there a way to stop it from running outside the application?
For example im trying to run the program in the background and when im browsing my facebook or on google it randomly keeps hitting enter.
Any help is greatly appreciated thanks for your time.
The short answer is to look at the windows available for a process and check the titles to see if it's the page you want.
If System.Diagnostics.Process.GetProcessesByName("firefox").MainWindowTitle = 'My Page Title'
...
End If
That said, there are much better ways to do this - If you're using firefox, look into GreaseMonkey, if in Chrome, look at TamperMonkey.
Both allow you to inject custom javascript into any page whose url matches a pattern you choose. In effect, you could write some Javascript to submit a form (say) 30 seconds after page load.
This would have the benefit of working if a different tab is selected as well as not requiring a whole application.
The SendKeys.Send method will indiscriminately send the key stroke to the active application. There is no way to use this API to target a specific application.
You could change your app to try and verify the active application is the one you want to send keys too. This is destined to be a flaky process though. No matter how good your verification is it's always possible that the active app is switched to another app after your verification completes.
If VerifyActiveAppIsTarget() Then
SendKeys.Send("{Enter}") ' Active app could change before this runs
I would persue a different solution for sending data between my apps
I'm buisy on a DirectX10 game engine and i'm having a problem which has nothing to do with DirectX :P The problem is that in the DLL which contains the engine sometimes a DialogBox is called, just like you would do in normal win32. With the only difference that instead of the HINSTANCE i use the HMODULE which i get when loading the DLL.
Everything seems to be working fine, if i step through my code with F10 (Visual C++ 2008) i can even see it going through my DlgMessageProc function and do everything it should do. The only weird thing is that no dialog is shown and that all of a sudden it jumps out of the message loop and just continues with the rest of the code???
Weirly engough I have the same problem when calling MessageBox from inside my DLL, I get no errors, everything seems to be working fine but no window is shown, nor is the code halted (as normal with messageboxes)
The funny thing is that I have some code from a book which uses the same basic architecture as me and if i compile that everything shows just fine??
So my question, is there any hidden option, pragama comment or other thing i should look at if i want to be able to show MessageBoxes and Dialogs from my Dll?
No as i thought, chaning the manifest doesn't help at all. I also created a separate project where i just test the dialog and its proc function and there everything works perfect (links to a .exe instead of dll)
In the visual studio resource editor's property page for the dialog resource there should be an option in which you can specify - "No Fail Create: True".
Usually dialogs fail to create because a common control cannot be created - usually because InitCommonControlsEx has not been called. Setting the No Fail Create flag lets you see dialog and determine which controls are missing.
Other things to check:
Is there a message in the debug window about a first chance exception? Perhaps its 'jumping out' because of an exception that is being caught and silently handled by Win32. Turn on debugging of first chance win32 exceptions in the Dev Studio exceptions dialog to track that down.
Even this wouldn't explain how a MessageBox call would fail to create a message box.
The only times Ive seen MessageBox fail to work were when:
Resource leaks had made the process run out of available user32 handles - have you checked your apps handle counts using task manager?
the system was in the process of being shut down. Have you called PostQuitMessage and then tried to create a dialog/MessageBox?