Beware the StrFind() Function in Microsoft Dynamics AX
Experienced developers who are new to AX and X++ can fall into the trap of making assumptions about what a function does based solely on its name. In the world of ERP, we are often called upon to troubleshoot another developer’s code, and that is the time to watch out for things like the StrFind() function.
I was recently tasked with figuring out why invoices were not printing under certain circumtances, but the users were unable to determine the difference in those invoices that printed successfully and those that did not.
To get to the point, I saw some code similar to the following…
(At this point in the code, the variable UserMenuSelection is set to ‘AutoInvoice’)
if (strFind(userMenuSelection, 'ABC', 1, 3))
userMenuSelection = strDel(userMenuSelection, 1, 3);
The code should be looking for the whole string ‘ABC’ and stripping it off the string in that situation, but this code should not affect ‘AutoInvoice’, right?. Wrong. The problem is that the strFind() function looks for any one of the letters ‘ABC’. It finds ‘A’ and deletes the first 3 characters, resulting in userMenuSelection ‘oInvoice’
In my customer’s case, this was causing some Automatic invoicing logic to be skipped.
Yes, I felt pretty stupid when I found this bug. In the back of my mind. I knew how StrFind() worked in X++, but my eyes skipped right over it several times.
If you are curious, what we need here is the StrScan() function