Monday, January 26, 2009

Another one!

I started getting a very unexpected error today in the application I’m working on. I did a quick search on google and resorted to asking a question on the StackOverflow website

The key ‘UserID’ does not exist in the appSettings configuration section.

Basically, I started getting this error while trying to open 2 of some 10+ forms in my Window Forms application in designer.

To prevent possible data loss before loading the designer, the following errors must be 
The key 'UserID' does not exist in the appSettings configuration section.

While waiting for a kind soul to reply to my question, I continued searching through Call Stacks, trying to find the cause of a problem. And I found it eventually. What the VS designer was really complaining about, was the fact that I was calling a stored procedure from the user control’s InitializeComponent.

Well, I have a couple of comboboxes on the user control which a populated from the database, so I decided to choose the simplest way to make sure they were populated by the time the user control was shown. Looks like it was not such a good idea. I ended up moving the calls into a separate function, and calling that function from a hosting form after the user control is shown in the hosting form. This appears to work for me. Took me a whopping 58 minutes to fix an error I introduced by being careless and ignorant, hope it’s not project-breaking thing.

by . Also posted on my website

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