IIF caught me out.

[jinnantonnixx]

Here's a good one.

 

I had a line of code:

  user.Initials = IIf(NewUser.MiddleName Is Nothing, "", NewUser.MiddleName.Chars(0))

 

Looks pretty straightforward.

If the NewUser.Middlename is Nothing, then user.Initials = "".

If the NewUser.Middlename is not Nothing, then user.Initials is the first character of NewUser.Middlename.

 

It kept throwing exceptions.

 

Well, it turns out that the IIF functions, rather than being the concise and efficient method I thought it was, is a bit rubbish.

It actually evaluates all three of the arguments every single time. Of course, if the NewUser.Middlename was Nothing, then NewUser.Middlename.Chars(0) will throw an exception, giving me my error. I presumed that it wouldn't get that far, but lo and behold it evaluated it every time giving me my exceptions.

 

Back to IF blocks.

 

https://msdn.microsoft.com/en-us/library/27ydhh0d%28v=vs.90%29.aspx

Edited May 24, 2016 by jinnantonnixx

[Willott]

Depending on the language (if c#), could you use the ? operator:

 

https://msdn.microsoft.com/en-gb/library/ty67wk28.aspx

 

Or ternary operator if():

 

https://blogs.msdn.microsoft.com/vbteam/2008/03/12/orcas-introduces-the-if-operator-a-new-and-improved-iif-sophia-salim/

[jinnantonnixx]

This project is in VB.NET. It's a minefield. I re-coded it so that the logic is unambiguous.

 

Nothing surprises me in VB.NET

Edited May 24, 2016 by jinnantonnixx

[Willott]

Go on... switch to C#... you know you want to