Variable Problem

Good morning Powershell people!! I am writing a script that needs to take a wait time parameter and pass it to Start-Sleep. My script works exactly as I expect when I hard code my wait time. The issue I am having is when I declare my parameter in the script and pass a default of 30, I get an error. Here is my declaration section:

param (
$Wait = 30


The error I am getting is on initiation of the script. I have googled, but my google-fu is weak today

[pre]: Cannot process argument transformation on parameter ‘Wait’. Cannot convert the “30”
value of type “System.Int32” to type “System.Management.Automation.ParameterAttribute”.[/pre]

Edit: A couple of things.

  • Parameter should have () or it probably would not validate properly. Although params don't need to be strongly declared (e.g. Mandatory=$true), it makes it easier to understand what you are doing.
  • [ValidateNotNullOrEmpty] isn't necessary, you a declaring it as an INT, so you have to pass a valid number to the cmdlet
  • int should be more than sufficient for sleep, no need to do int32
  • The variable should be $WaitInSec or something that tells a user what time measurement is being used. Minimally help provided to ensure they understand it's seconds vs minutes.
param (
    [int]$Wait = 30

Rob, Thanks for the quick reply. It didn’t change the behavior. Here’s the output:

PS C:\WINDOWS\system32> [CmdletBinding()]
>> param (
>> [Parameter(Mandatory=‘False’)]
>> [String]$Environment,
>> [ValidateNotNullOrEmpty]
>> [Int]$Wait = 30
>> )

cmdlet at command pipeline position 1
Supply values for the following parameters:
Environment: TEST
Cannot process argument transformation on parameter ‘Wait’. Cannot convert the “30” value of type “System.Int32” to type “System.Management.Automation.ValidateNotNullOrEmptyAttribute”.
+ CategoryInfo : InvalidData: (:slight_smile: [], ParentContainsErrorRecordException
+ FullyQualifiedErrorId : ParameterArgumentTransformationError


Good points. Let me implement and see if that fixes the issue I am seeing. The reason I used [ValidateNotNullOrEmpty] is so I can pass the default of 30 seconds if the user doesn’t specify a wait time.

You are setting a default value, so if a user does not pass a value it will use that. If a user does pass a value, it has to validate to be a numeric number in the int range.

function Test-It {
param (
    [int]$Wait = 30

    'Waiting {0} seconds for environment {1}' -f $Wait, $Environment


Test-It -Environment Alpha


PS C:\Users\rasim> Test-It -Environment Alpha

Waiting 30 seconds for environment Alpha

PS C:\Users\rasim> Test-It -Environment Bravo -Wait 3
Waiting 3 seconds for environment Bravo

PS C:\Users\rasim> Test-It -Environment Bravo -Wait 
Test-It : Missing an argument for parameter 'Wait'. Specify a parameter of type 'System.Int32' and try again.
At line:1 char:28
+ Test-It -Environment Bravo -Wait
+                            ~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Test-It], ParameterBindingException
    + FullyQualifiedErrorId : MissingArgument,Test-It

PS C:\Users\rasim> 

It was the [Validatenotnullorempty] that was causing the problem. I modified it to what you have and no issue. Thanks.