Need help with ValidatePattern

PowerShell Help
1

I am trying to validate user input using ValidatePattern

param (
[Parameter(Position=0,mandatory=$true)] # Parameter is mandatory
[ValidatePattern(“^\d{4}$”)]
[int]$UserIp
)

  $GtVer = $UserIp.ToString()
  
  $GtVer

This code worked perfectly fine in PS 3.0 but failed in 2.0 throwing below error. How can i achieve this in PS 2.0 ?

Parameter attributes need to be a constant or a script block.
At D:\Scripts\Paramv.ps1:3 char:39

  •         [ValidatePattern("^\d{4}$" <<<< )]
    • CategoryInfo : ParserError: (:slight_smile: , ParseException
    • FullyQualifiedErrorId : ParameterAttributeArgumentNeedsToBeConstantOrScriptBlock
2

Out of curiosity, have you added [CmdletBinding()] just above the param() block?

3

Hi Don Jones

Thank you for helping me, I tried that as well but no avail.

4

I got it right when i used single quote instead of double quotes, However it works in both ways with PS 3.0 !

[ValidatePattern(‘^\d{4}$’)]

Thank you

5

Looks like that trailing $ causes problems in PowerShell v2, even though it doesn’t actually cause any expansion to take place. It worked when I put a backtick before the $ (in a double-quoted string). In this case, though, single quotes are more appropriate anyway.

6

Ah, beat me to it. Ya, dug out a v2 VM and observed the same thing. Strikes me as a bug, which is obviously fixed, but a search in Connect didn’t turn anything up. Likely the team noticed it and fixed it internally for v3.

Anyway, Nithun, there’s a kind of “good practice” to use single quotes unless you explicitly need the feature of double quotes (variable replacement, escape characters, subexpressions), which helps avoid this problem (as Dave suggested).

7

Thank you so much Don and Dave for the inputs, I am very new to powershell.org and it was my first post here.
Feel so special and blessed to be a part of this.

Good day
Nithun

8

http://www.microsoftvirtualacademy.com/Content/ViewContent.aspx?et=3447&m=3441&ct=18346#?fbid=SD-xryBRFvI

Go to this video and jump to the 19:24 mark or they have it bookmarked on the right.

Even better watch the whole video > even better the whole series is so awesome and has helped me greatly!

-VERN