How to allow users to quit out of long-running VBA tasks? - vba

I have a routine that examines thousands of records looking for discrepancies. This can take upwards of 5 minutes to complete and although I provide a progress bar and elapsed time count, I'm not sure I want to encourage folk pressing ctrl-break to quit the report should it be taking longer than expected.
A button in the progress bar won't work as the form is non-modal, so is there any neat way of allowing users to quit in this situation?

You need DoEvents and a variable whose scope is greater than the scope of what you're running. That is, if it's just a procedure, you need a module level variable. If it's more than one module, you need a global variable. See here
Stopwatch at DDoE
Normally, the VB engine will tie up the processor until it's done. With DoEvents, however, VB allows the processor to work on whatever is next in the queue, then return to VB.

I don't think there is a way to do it like you would want it to work. VBA is a scripting language so when you start your procedure, it's gonna run until it's done. If you had another button somewhere that even WOULD let you click it while the original procedure was running, I'm not sure how you would reference that procedure and stop it.
You could do something like ask the user if they want to contine, but that would make it run even longer.
Also you could have your procedure check for a condition outside of Excel and keep running as long as it's true. Something easy might be check if a certain text file is in a folder. If you wanted the procedure to stop, open the folder and move the file. On your loop's next iteration, it wouldn't see the file and stop running. Cludgy, inefficient, and not elegant, but it would work. You could also have it check a cell, checkbox, radiobutton, basically any control in another Excel sheet running in another instance of Excel. Again cludgy.
CTRL+Break works. Accept it and move on. One neat trick about that though, is that if you password protect your code and they hit CTRL+Break, the debug option is unavailable and they will only get Continue or End.
If this is code that is run frequently, have you considered scripting something that runs it during times when a human is not using the computer? I used to run telnet screen scraping macros that would take hours to go through our widgets, but I always had them run either on a separate computer or when I wasn't there (nights/weekends).

Related

Prevent >1 person from running VBA macro at a time (shared wkb)

What I'm aiming at is getting a list of all currently running scripts in order to check if other users aren't running the same VBA macro at the same time (and if yes, then stop the code etc., similar to what the OP of the below question wanted). This would be for a shared workbook (I learned it's not designed for this type of work, but I need to try it).
https://stackoverflow.com/a/36116091/5947935
I've been trying to make the code in the above answer work in VBA, but it seems it's a vbs thing and I would like to avoid that.
I'm not an expert to say the least, so I'm having trouble understanding how to get this to work in Excel VBA. I don't even know if it's possible at all.
I've found this as well: VBA Getting program names and task ID of running processes and it works fine but it only lists the running processes.
I've no idea however how to merge the two... or even if the WMI is the correct way to go.
I'd appreciate any sort of help.
I used to create a "locking file" which was just an empty text file with the name of the workbook followed by the username and an extension of .LCK
First thing my code did on auto open was look for a locking file then report back to the user which user had it open then cancel the open.
If it didn't find a locking file then it created one and proceeded as normal. If it found one but it was the same username (ie that user had it crash on them) it proceeded with the open.
The last thing the code did was delete the file.
No codes here and theory not tested yet, but the idea of preventing a different user executing a Macro on a shared workbook requires some thinking.
I would create a hidden worksheet, and use one of the cells to store the Environ("USERNAME") when the macro is first started - to indicate who has it running, then clear it when complete, first-in-first-out.
Lets say named range MUser (macro user) is range A1 in that hidden worksheet
When the macro runs, it will first check if MUser is empty, if so then change it's value to Environ("USERNAME") and Save the file before next step (here I am not certain the value is updated on others session).
If MUser is not empty, either abort or retry in a few second.
When macro completes, MUser will be ClearContents, and save the File to free up the workbook for macro.
Idea is here but please test. Post your own code for us to troubleshoot. You may also use Workbook events to "lock" the macro execution this way. Or even use this hidden sheet to make a log record for debug. Also some fail-safe needs to be implemented (such as a time stamp at macro start and override the lock after some minutes).

Running a block of code in the background of AppleScriptObjC app?

Is it possible to have a block of code constantly running or 'repeating' in AppleScriptObjC, whilst the rest of your script is still active? I've got a block of code that I want to repeat in the background that checks to see if a folder exists and creates it if it doesn't, but if I set it to repeat indefinitely then I lose the ability to access the other buttons and code blocks in my app?
Apologies if there isn't enough info here or it's a bit confusing!
I'd probably create a repeating NSTimer to do the check at a specified interval. That would avoid blocking your main thread.
Depending on the app, perhaps you could also just check for the existence of the folder and create it just in time, when you really have a need for it.

How to close/stop a .NET application and re-execute it?

My application updates(running a vba script) an excel shared workbook, and since it is shared, there shouldn't be problems when someone else is using the same file at the same time. But for some reason, sometimes it simply freezes, without any error message, just freezes.
Is there a way to programatically make the application stops/closes automatically when frozen or after some minutes(In normal conditions, this updating process shouldn't take more than 1 minute)?
And, if possible, re-launch the app again automatically after some minutes for at least 5 attempts?
This way would ensure process completes succesfully.
I have had to do this same thing before but because I had an application that would look for updates to it's self on the network and then update it locally. Problem is, you cannot update the exe that is running.
What I did to get around it is to create another program that would wait a second, update the exe, then run the exe again.
Because I did this with a few different apps, I made my "Updater" generic so I could send some command line parameters and it would use those to copy and run.
If you want to try something else, you might be able to accomplish this same thing by creating a BAT file and running it. I'm not real good on BAT files so I can't help you there. But, it is another way to handle it.

prevent button press across instances

I have created a database/app where a report is created when a particular button is clicked. just now, two people managed to hit the button at exactly the same time, which caused all sorts of not-good.
Is there a way to make a button invisible across instances once it's clicked by one person? Or some way to lock the database so nothing can be done until the person who clicked first is done?
I have a solution (basically, a global check variable that stops the report creation) but now I want to know if either of the other two options can be done.
It would really help to know more about your architecture here. What database? What language have you written your application in? Concurrent reading is usually an important and basic feature of most multi-user databases.
Seconding Daniel Cook's general notion, maybe explicating a bit: don't have the button run the report directly. Have it run a little subroutine that first checks a special purpose table where you represent report "runs" with a new record that has a start date-time and an end date-time. If there is a record sitting in the table with no (null) end-date, then the report must still be running, therefore, do NOT begin report, turn off button instead. Else, insert into that same table and then start running the report. Add to this a periodic, not-too-frequent callback on that button to perform the same check, and you've got something that comes close, but isn't "realtime", but should work in most architectures (not knowing anything about session management capabilities).
Here's what I did:
If DLookup("PayLock", "table", "pkID=1") Then 'it's locked - exit
MsgBox "Someone else has already started the pay process.", vbOKOnly
Exit Sub
Else
blah blah blah......
The "PayLock" field in the table holds the check variable. After "Else" comes the actual code to run when the button is clicked.
Just FYI, since they were asked:
it is split database
there are multiple users
yes, the report just reads data and exports it into an excel spreadsheet.
It looks like this is the only solution, which works, but seems inelegant. I keep discovering that the way I get around my lack of knowledge is the actual way to do it...

VBA maintaining the program in memory

Sorry I don't know if this is something simple, or even where the problem fits in the greater scheme of programming.
So in my unsophisticated ways, my programs have always been of the scheme: 1. start program, 2. wait while program runs, 3. program is done and gone.
What I am doing now is creating a table from a long list of transactions (10,000s of). The table has several combo boxes for the user to select filters. Right now, every time the user changes a filter, the entire log is re-processed, which takes half a minute or a minute.
What I would rather do is have the trade log held in memory, or somehow latently but more immediately available. But not have the program "spinning" in the background. So the user could go about using Excel unaware that the program is ready in the background in case they want to update the table later, or not.
Does that make sense? If it can't be done in VBA, I'd still be curious how it would be done in another environment, say C#, if it could be. Thanks.
If the frequency of updates to the options trade is low enough you could separate reading and processing the option trades from the filtering process:
Step 1 - Refresh - read the logs and process them, storing the results in global containers (arrays, collections, dictionaries, objects ...)
Step 2 - User requests - show form - user chooses filters - show/store results extracted from the global containers.
There are several options
Firstly, is the code correctly structured? For example, do you really need to re-process everything or can a re-write be more efficient?
If you cannot avoid resource intensive code, notify the user with a progress bar or message. Also consider the use of DoEvents which frees up the operating system so that Excel can process other events.
DoEvents is slow and dirty. Even better look at this link DoEvents is slow!!! Here are faster methods
Rewrite your code to work asynchronously. Create a class, a handler and deal with each transaction asynchronously.
You could write some VBScript/Javascript and push the task out to run independently of Excel/VBA. Eg there's an example Here
Don't use VBA :)
Edit: How are you filtering? If you're iterating through thousands of items in an array testing for criteria it can be very slow. Excel's Advanced Filter is very quick and could process hundreds of thousands of rows with multiple criteria quickly.
When a macro in Excel VBA runs, the user cannot use Excel anymore, running the VBA "stucks" the whole program.
Here are a few tips to find a workaround for your problem :
Keep the vba running : load the data a first time when launching the combobox and then display results to the user every time he asks for but keep a combobox loaded so that vba keeps its context and memory
Load the data in Excel Worksheet, even hidden and then use it when the user asks for some data
Give us more info on what you are doing, from where you are loading the data, how you can cache it, what is your current code, what you tried... so that we can help you more
Regards,
Max