MS Access Invalid use of null error

[Accrj19]

I inherited a database at work and everything was working fine for about 4 months. All of a sudden, I started getting an "Invalid use of null" error when I tried to open an unbound main form that contains a bound subform. The subform has a query as its data source.

After many hours of analysis, it turns out that on the subform there is a text box whose control source property is a function. This function is being called before the Current event and all of the variables are null even though the variables are part of the query that make up the subform's record source. That is when I get the "Invalid use of null" error message.

Oddly enough, everything works fine for some users. For these users, the Current event fires before the text box's "control source" function and so the variables all have values. But the code is exactly the same, so I don't know what to do.

I'm very confused and any feedback would be appreciated.

Thanks.

[Rabbit]

You'll need to handle the null. Probably through Nz or something. But that's all I can say unless you post the code.

[zmbd]

You also need to tell us the versions of everyone using the database. Has there been a recent upgrade?

[Accrj19]

@Rabbit
Rabbit,

Thank you so much for responding. Sorry I haven't responded sooner but I have been away from my job for the last week.

But your answer got me to think simply. I check for a null value and the beginning of the function, and exit if null. It seems to work.

I'm still perplexed as to why the functions are not executing in the same order but I have so much on my plate at work, I can't spend too much time on this now.

[Accrj19]

@zmbd
Hi, zmbd,

The database was originally written in Access 97 and upgraded to 2010 (I had no part in either process). I made some major changes to the database and fear that I decompiled incorrectly.

All users are using 2010.

Thanks for replying!

[zmbd]

the code would be helpfull; however, I'm afraid that what is going to happen is that you will have to create a new file in the current version of access and then import everything from the old file into the new.

There's a bug when using an file created in an older version of access with a new version of Access, even if the file does open. The most reliable fix has been to create a new file in the current version of access (even if it is in the older format) and then import everything from the old file into the new.

One of the wonderful things with MS.