For my customer i had to do a change in a visual basic 6 application running on a windows xp computer.
It's nothing special, just communicating with a plc and functions as a user interface.
My changes work absolute perfect in developer environment(IDE), but when i create the exe it crashes when opening some forms or pressing some buttons. Some stuff works, and some stuff crashes.
Compiler in develop doesn't give any errors even after full compile!
I found some "bugs" by iterating the code and this really is just deleting some variables. (that already existed + It isn't a programmable error) The compiler doesn't give an error, just the exe crashes on it.
An example from bug that crashed:
sub On form_load()
Some code
Global_String_Variabel = "Something"
some code
End sub
By deleting the global string variable just in this form, it didn't crash any more.
It's weird because this peace of code already existed, works perfectly fine in develop but not in .exe
Does somebody have any idea why this could happen?
If I understand your question correctly, the program runs on your development machine both in IDE and compiled in both states, with the string assign and without, yet works only without on the client's machine. Something like this happened to me many years ago, and while it may not be your problem, you might at least be able to rule it out. The client may have a virus scanner that erroneously thinks that a segment of your code is malware. Just adding another line like x = x or something else benign can sometimes fix it.
You may also need to look further into other differences, like other things they have/run that you don't.
Not that it should matter but are you declaring the variable somewhere and using Option Explicit?
Related
This is something I didn't think was even possible, but here goes. I was trying to learn how to use the Windows API in Visual Basic to use system calls, and this tutorial (yes, I had to type out the link manually to ask this question, more on that later) showed me how to use the clipboard to retrieve text that the user copied with Ctrl+C. Out of curiosity, and under the assumption that all user input is bad input, I tried pressing Print Screen and then running the code just to see what would happen. I got some error message (can't remember what) but what's very strange is, now the clipboard no longer works! Any attempt I make to paste after a cut or copy, no matter what program I'm using, either does nothing or returns an error message in the program I'm using it in. Yes, it's my fault for intentionally trying to break the code example, but let's be honest - there's no excuse for the OS to fall apart so easily. If it matters, I'm using a PC running Windows 10.
EDIT: Settings won't let me clear the clipboard, and when I try to view the clipboard history, it shows nothing is there. Unfortunately I wasn't able to screenshot the clipboard history because it closes by itself when I try to open Snipping Tool.
Sounds like you've missed a CloseClipboard(), keeping the clipboard locked since Windows thinks a program is reading to it or writing from it. This will prevent other programs from working with the clipboard, since only one program can access it at a time. If Access is still open, you can try running CloseClipboard in the immediate window, else, I recommend a reboot.
On code like this, always add an error handler that calls CloseClipboard() to prevent leaving the clipboard open if something unexpected happens. Note that when working with WinAPI, you might encounter hard crashes that may not call the error handler, so always triple-check your pointers and expect crashes and reboots.
The code you've found is also not adjusted for 64-bit use, so beware. If you've got it to work by just slapping PtrSafe on the functions, you may end up with invalid pointers which can crash Access, leaving the clipboard open and unusable.
The code you've found, while written by Microsoft, is not of particularly good quality. I recommend first checking if there's text on the clipboard using EnumClipboardFormats, then only requesting text if there actually is text on the clipboard.
Beware that using WinAPI through VBA is tough, it's not beginner stuff, especially regarding the clipboard.
Note that there's no excuse for the OS to fall apart so easily is not the attitude to have when working with WinAPI. You're directly interfacing with the OS without any of the securities that managed languages offer, and manually working with pointers. It can and will break if you do something invalid. There's a reason most people use libraries that abstract the dangerous stuff away, if you don't, all bets are off.
similar problem for me. I did not have a CloseClipboard() but when I looked in another module there was already a EmptyClipboard() so used that before the DupRec() call at each instance and no more problems with clipboard. just FYI
I've been using Visual Studio 2010 for years now. I have a fairly complex VB.net project that I routinely make changes to. Recently, whenever I'm making changes in debug mode, it throws a System.InvalidProgramException - Common Language Runtime detected an invalid program error which forces me to stop running the program and then restart it again after I've saved my changes.
This issue only happens when I make changes to a Sub or Function which is called by another Sub or Function. For example, if I make a change to a button click event, it's fine, but if I make a change to a function that button calls, it errors.
A change as simple as adding blank lines in my code will cause this to happen. No code change at all...just literally hitting return to add blank lines between code lines.
I installed Visual Studio 2013 thinking it would solve this. It does not. I still get the same errors.
I tried moving my project files to a different HDD, I still get the same errors.
I thought maybe I have corrupt memory, so I ran a full checkdisk and defrag but I still get the same errors.
I've read where this error may happen with very large procedures or projects with lots of variables (although I thought this was fixed in newer .NET versions) so I've cleaned up my code. The largest Module has 30k lines.
The workaround is to stop the project running, save my changes and then restart it...however, that takes time because my program has to reinitialize everything when it runs, so I'd prefer to be able to make changes while debugging.
Also, I have .NET framework 4.5 installed
Update: I loaded up a backup of my code from a month ago and it runs fine...so apparently some recent changes I've made are causing this error. Once I figure out what's changed, I'll update this just for future reference in case anyone else runs into the same issue.
I am in the beginning phase of a new VB.net Windows Forms project in VS 2013 that is connected to a TFS 2013 application tier. I have updated the VS client using Microsoft Update to include all hotfixes available for it at the current time.
There are 2 problems that I'm having:
Breakpoints are ignored (eventually)
F10 (Step Over) & F11 (Step Into) don't work properly (They work maybe once or twice, then totally step out of all running methods)
The problem morphs as time goes on, but here is essentially what happens (NOTE: I have a breakpoint already set in a method that is called on Form Load, so the expected behavior is that the breakpoint is hit before the interface is usable. Also, there are about a dozen lines after the breakpoint in the method)
F5 to start the project in debugging mode
The form loads and does not stop at the breakpoint
Make a change that calls the method
The application stops at the proper point
Hit F10 once, it goes to the next line
Hit F10 again, it completely steps out of all running methods, bringing me back to the interface (What I expect here is for it to go to the next line)
Repeat steps 3-6 consistently until it just continues and does not stop at the breakpoint again, nor does it allow me to Step-Through or Step-Into any methods
Some additional information:
I have another, larger in size VB.Net application that has never experienced issues with debugging
When I set up VS2013, I chose General Development, and the only change I made from the default settings was to change the color scheme to the dark scheme.
In my research, the only articles I have really found pertaining to 2013 that were even remotely relevant all pointed to this article: VS/2013 Debugger Not Working (MFC/C++/CLI w/ previous version of MFC library)
This article sounds like it has similar behavior, but it's pertaining to projects that contain both C# and C++ code, which mine does not.
Does anyone have any insight as to what could be causing this, and what I can do to work around it? I didn't have these issues with VS2012 and I think I will probably use that for this project until I can get the issue resolved.
Ok, I found the problem.
It stemmed from the fact that each of the lines I was trying to step over or into had an InvalidCastException (I was trying to add an Integer and 2 Strings together, and stick them in another string. When the strings were blank, it was trying to convert them to Double). These errors were NOT causing the application to break, it was silently ignoring them and putting them in the Output window (Which I wasn't paying attention to).
The irony is that I knew there were going to be errors on those lines, and I was trying to figure out what they were so I could do the conversions properly.
The breakpoints failed when I had one of the lines set to break that was generating the error, and the Step Over functions would completely skip past them.
Once I fixed the InvalidCastExceptions, debugging started working properly again.
Having a very odd issue with Visual Studio 2013, curious if anyone else is seeing anything similar. I have VS 2013 Ultimate, it seems like once a day, while I'm working with a file, the compiler just suddenly freaks out and doesn't detect my code anymore in my web forms. Take a look at the screenshot below (I just chose a random spot in the middle of the web form), but out of nowhere, VS starts erroring, telling me that variables aren't declared, that method arguments need parenthesis on lines of code that aren't methods, all sorts of whacky stuff.
I assure you, I don't have any broken references, I didn't forget to close an if statement.. nothing like that. All I'm doing it writing some code, and randomly the whole page just starts to error like this. To resolve, all I can do is copy the code contents, delete the page, recreate the page, and paste the contents back into my "new" file... same exact code, only no errors. I wouldn't even worry about doing this if I wasn't doing this at least once a day.
Any help is appreciated, thanks!
Edit: For what it's worth, I found a slightly easier workaround for this issue. If I edit the properties of the class file to "Do not Compile" and then back to "Compile", the IDE is able to read the file just fine...
It looks like this is simply a bug in the Vb.Net Compiler / IDE. I agree it's unlikely to be a bug in your code because you can see that the error squiggles don't line up with places that would represent the errors you are reporting. This is sometimes a sign of an IDE bug
In terms of fixing the problem though you can probably get them to go away by closing and reopening the solution in question. Baring that restarting Visual Studio. I wouldn't resort to deleted / recreating the page.
Long term though you may want to file an issue on connect so the IDE team can try and fix the problem.
http://connect.microsoft.com/VisualStudio
I'm new to VB6 but i'm currently in charge of maintaining a horror of editor like tool with plenty of forms, classes, modules and 3rd party tools all chunk together like the skin faces on that guy in the texas chainsaw massacre...
What i don't understand is why i get different results when i run the app in debugging mode, vs when i compiled it and run it on my devevelopment pc vs when i installed it on a different pc.
Yes i know i'm dumb, so please direct me to where i can find out more about this. I'm hoping to find out something like different linking, registry related etc connection that i'm simply not getting right now, i.e. something like wax on, wax off :P
The main pain in the neck is when i'm trying to debug some errors from my QA and i need to find a spare pc to test this on plus i can't directly debug because i don't know where the code is if i do it that manner.
Thanks.
i run the app in debugging mode vs when i compiled it and run it on my
devevelopment pc
When you compile you have the option of compiling to native code or pcode. The debugger runs using pcode only. Under rare circumstances when you compile to native code there will be a change in behavior. This particular is really rare. I used VB6 since it's release and I may get it once or twice a year. My application is a complex CAD/CAM creating shapes and running metal cutting machine and has two dozen DLLs. Not a typical situation. At home with my hobby software I never ran into this problem.
There are another class of errors that result from event sequencing problems. While VB6 isn't truly multi-tasking it has the ability to jump out of the current code block to process a event. If it re-enters the same block for the new event interesting things (to say the least) can result. I think this is the likely source of your problems as you software is an editor which is a highly interactive type of software.
In general the problem is fixed by reordering the effected areas. You find the effected area by inserting MsgBox or write to a text file to log where you are. I recommend logging to a text file as MsgBox tend to alter behavior that are timing or multi-tasking related.
Remember if a event fire while VB6 in the middle of a code block and there a DoEvents floating around then it will leave the code block process the event and return to the original code block. If it re-enters the same code block and you didn't mean for this to happen then you will have problems. And you will have different problems on different computers as the timing will be different for each.
The easiest way to deal with this type of issues is create some flag variables. In multi-tasking parlance they are known as semaphores or mutexes. WHen you enter a critical section of code, you set it true. When you leave the routine you set it to false. If it is already true when you enter that section of code you don't execute it.
when i installed it on a different pc.
These are usually the result of the wrong DLL installed. Most likely you have an older version while the target has a newer version. I would download the free Virtual PC and create a clean Window XP install to double check this.
If your problem is event timing this too can be different on different computers. This is found by logging (not MsgBox) suspect regions.
If you can display a screen shot or the text of your specific errors then I can help better.
The first thing to check would be the versions of all the dlls that your app depends on - including the service pack version of the VB6 dll.
Have you any more specific details about what's behaving differently?