# Need help with ValidatePattern
**URL:** https://forums.powershell.org/t/need-help-with-validatepattern/2264
**Category:** PowerShell Help
**Created:** [February 13, 2014, 7:07am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264 "2014-02-13T07:07:11Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@nithun-damodaran](https://forums.powershell.org/u/nithun-damodaran)
#### Post date: [February 13, 2014, 7:07am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/1 "2014-02-13T07:07:11Z")
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: (🙂 , ParseException
- FullyQualifiedErrorId : ParameterAttributeArgumentNeedsToBeConstantOrScriptBlock
---
### Author:  [@donj](https://forums.powershell.org/u/donj)
#### Post date: [February 13, 2014, 7:10am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/2 "2014-02-13T07:10:35Z")
Out of curiosity, have you added [CmdletBinding()] just above the param() block?
---
### Author:  [@nithun-damodaran](https://forums.powershell.org/u/nithun-damodaran)
#### Post date: [February 13, 2014, 7:17am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/3 "2014-02-13T07:17:26Z")
Hi Don Jones
Thank you for helping me, I tried that as well but no avail.
---
### Author:  [@nithun-damodaran](https://forums.powershell.org/u/nithun-damodaran)
#### Post date: [February 13, 2014, 8:05am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/4 "2014-02-13T08:05:45Z")
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
---
### Author:  [@system](https://forums.powershell.org/u/system)
#### Post date: [February 13, 2014, 9:06am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/5 "2014-02-13T09:06:09Z")
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.
---
### Author:  [@donj](https://forums.powershell.org/u/donj)
#### Post date: [February 13, 2014, 9:27am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/6 "2014-02-13T09:27:05Z")
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).
---
### Author:  [@nithun-damodaran](https://forums.powershell.org/u/nithun-damodaran)
#### Post date: [February 13, 2014, 10:27am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/7 "2014-02-13T10:27:21Z")
Thank you so much Don and Dave for the inputs, I am very new to [powershell.org](http://powershell.org) and it was my first post here.
Feel so special and blessed to be a part of this.
Good day
Nithun
---
### Author:  [@vern\_anderson](https://forums.powershell.org/u/vern_anderson)
#### Post date: [February 14, 2014, 1:25am UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/8 "2014-02-14T01:25:17Z")
[http://www.microsoftvirtualacademy.com/Content/ViewContent.aspx?et=3447&m=3441&ct=18346#?fbid=SD-xryBRFvI](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
---
### Author:  [@dotnVo](https://forums.powershell.org/u/dotnVo)
#### Post date: [May 16, 2024, 8:52pm UTC](https://forums.powershell.org/t/need-help-with-validatepattern/2264/9 "2024-05-16T20:52:25Z")