Need help with ValidatePattern

This topic contains 7 replies, has 4 voices, and was last updated by  Vern Anderson 4 years, 4 months ago.

  • Author
  • #13099

    Nithun Damodaran

    I am trying to validate user input using ValidatePattern

    param (
    [Parameter(Position=0,mandatory=$true)] # Parameter is mandatory

    $GtVer = $UserIp.ToString()


    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: (:) [], ParseException + FullyQualifiedErrorId : ParameterAttributeArgumentNeedsToBeConstantOrScriptBlock

  • #13100

    Don Jones

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

  • #13101

    Nithun Damodaran

    Hi Don Jones

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

  • #13102

    Nithun Damodaran

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


    Thank you

  • #13103

    Dave Wyatt

    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.

  • #13105

    Don Jones

    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).

  • #13106

    Nithun Damodaran

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

    Good day

  • #13109

    Vern Anderson

    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!


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