manage items in a list box

[gemma-the-husky]

I have a list box on an unbound main form, which contains a rowsource consisting of files in a certain folder. The listbox is unbound

when I change an item in a subform, the listbox should update to show different items from the same folder.

Now it is updating correctly, so the rowsource appears to be correct, , but then the listbox behaves strangely - with the first item being sort of permanently selected - or at any rate - strange selection behaviour

Anyone seen this sort of behaviour?



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out of interest, changed it to a combo box and it works correctly. so there must be some difference between the two?


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After investigation, it might be this

http://stackoverflow.com/questions/3843784/listbox-is-selecting-many-items-even-in-selectionmode-single

the appearance is similar to what is described in the thread.

although I have played with the strings to get them shorter without getting it work correctly. very strange

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further

if I run the code to update the listbox from the subform, either directly, or by running as sub IN the main form, it produces this strange behaviour. If I run exactly the same code directly IN the main form, it seems to work properly.

 

[CJ_London]

is the listbox set to multiselect? It may be you need to set the selected property to no.

 

[gemma-the-husky]

no - the code is right.

- after playing around, and a lot of testing, it appears to be an issue caused only by updating the list box either by using code directly the subform, or by calling a proc in the mainform.

I have got round it, by not trying to use the subform at all, but just clicking a "repopulate" button on the main form, which uses exactly the same bit of code.

 

[Uncle Gizmo]

As I understand it, running code in the subform, or running a procedure on the main form with code from the subform causes the problem.

Running code from a command button on the main form does not cause the problem.

Have you tried a refresh or repaint?

 

[gemma-the-husky]

tried everything, requery, doevents, etc etc

the combo box populates, but then behaves strangely. The appearance is like the link I mentioned, but the values are definitely all different. I can only think the interaction between the subform and the mainform does something to prevent the list box functioning exactly correctly.

The strange thing is - once the subform "screws up" the list box behaviour, the mainform then doesn't help it work properly.

 

[Galaxiom]

Unbound combos definitely have bugs.

FWIW Try reading the Text property of an unbound combo on a form with a filter that returns no records.

 

[Uncle Gizmo]

I recently upgraded someone else's MS Access database (Never Again) to an SQL Server back end with a runtime front end on a Citrix environment. Everything worked fine in my local MS Access copy; however I had numerous strange breakages within the MS Access runtime environment. I discovered that everything in the runtime environment had to be explicitly declared and addressed. I'm wondering if something similar is happening here and you need to specifically address the form.

 

[gemma-the-husky]

nice thought, Uncle Giz - but no joy

I am going to try and put together a demo I can upload.
It might just be this dbs/form - so it is worth doing.

 

[gemma-the-husky]

Right

I just created a demo, and it worked correctly - so I must have a corruption in my form.

So I will create a new form, and try again.

 

[gemma-the-husky]

fixed it in a different way

I never got to the bottom of it. Instead, I decided to push the files into a temp table, and base the listbox on the table - and it works fine now.

 

[Galaxiom]

My preferred technique for listboxes is the fabricated ADO recordset. They can easily be loaded directly using a loop though anything. Ideal for listing things like filenames, tablenames etc.

Not having a table base they avoid the need for requerying anything by the engine.

Plus you get the Filter and Sort methods which are are far simpler to use than reorganising a list rowsource.

 

[gemma-the-husky]

Galaxiom.

yes, the idea of using the rowsource string was to keep it all in memory, rather than have to use a table. I am not familiar with ADO, though - do you have a link

I don't need to sort it as - the file names incorporate the date, I just needed to collect the data.

 

[nanscombe]

If you just needed to collect the data, rather than display it, you could have used an Array.

 

[Galaxiom]

Here is an example of listing files.

 

[gemma-the-husky]

I want to use it. The list box shows the files associated with a givenselection, so that they can be selected and used.

 

[Galaxiom]

Are you sure a file selection dialog window would not be a prettier solution?

 

[gemma-the-husky]

no - it's all working now

effectively, this is what I am doing

I have a folder that is going to save pdfs of documents

when I navigate to a different customer, I want to pick up all the documents previously sent to this customer, so I am doing this by a matching file search on the folder. Then the user can just select any of these to open without having to do any browsing. I want the list to be available without the user having to open a file browser.

my initial idea was to build these into a row source for a list box - but because of the problem I had, I am now storing the details in a temporary table, which is working fine.

Interestingly, putting the file list into a row source for a combo box didn't produce any problems - but for this I wanted a list box.

And the demo I tried to put together also worked correctly. I actually rebuilt both forms completely to see if there was a minor corruption, but it still didn't work - so something is going on.


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here is a working demo of what I was doing

just create a subfolder in the project path, create a few dummy files, and enter details in table1 to filter some of the files, then open form1

ignore the bit in the middle. that was a deliberate attempt to stop it working

View attachment listboxdemo.zip