Dynamic Parameter cannot be specified in parameter set '__AllParameterSets' - powershell

Question

Hello, I am trying to create a dynamic ValidateSet that is based on the contents of a simple text file for one of my cmdlet parameters. I followed this blog post https://blogs.technet.microsoft.com/pstips/2014/06/09/dynamic-validateset-in-a-dynamic-parameter/, and I came up with the following:
function Remove-NetScalerWhiteListItem
{
[CmdletBinding()]
Param
(
)
DynamicParam
{
$ParameterName = "ServiceGroup"
$AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]
$ParameterAttribute = New-Object System.Management.Automation.ParameterAttribute
$ParameterAttribute.Mandatory = $true
$ParameterAttribute.Position = 0
$ParameterAttribute.DontShow = $false
$serviceGroups = Get-NetScalerWhiteList
$ValidateSetAtrribute = New-Object System.Management.Automation.ValidateSetAttribute($serviceGroups)
$AttributeCollection.Add($ValidateSetAtrribute)
$RunTimeParameter = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)
$RuntimeParameterDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary
$RuntimeParameterDictionary.Add($ParameterName, $RunTimeParameter)
$RuntimeParameterDictionary
}
Begin
{
$ServiceGroup = $PSBoundParameters[$ParameterName]
}
Process
{
Copy-Item "$masterIgnoreFilePath\ingnore.txt" "$masterIgnoreFilePath\ingnore.bak"
$serviceGroups = Get-NetScalerWhiteList
$serviceGroups.Remove($serviceGroup)
Write-Host $serviceGroups
}
}
This partially works, if I begin by typing Remove-NetScalerWhiteListItem -ServiceGroup my validation set is there and working, however when I select one of the items and run the command I get the following error:
Remove-NetScalerWhiteListItem : Parameter 'ServiceGroup' cannot be specified
in parameter set '__AllParameterSets'.
At line:1 char:1
+ Remove-NetScalerWhiteListItem -servicegroup servicegroupname
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Remove-
NetScalerWhiteListItem], ParameterBindingException
+ FullyQualifiedErrorId : ParameterNotInParameterSet,Remove-
NetScalerWhiteListItem
As for the line $serviceGroups = Get-NetScalerWhiteList that is just a wrapper around a Get-Content call to a specific file.

Answer 1

I think you need one more line. You never add the $ParameterAttribute to the $AttributeCollection. You can do so by using this line $AttributeCollection.Add($ParameterAttribute).
function Remove-NetScalerWhiteListItem
{
[CmdletBinding()]
Param
(
)
DynamicParam
{
$ParameterName = "ServiceGroup"
$AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]
$ParameterAttribute = New-Object System.Management.Automation.ParameterAttribute
$ParameterAttribute.Mandatory = $true
$ParameterAttribute.Position = 0
$ParameterAttribute.DontShow = $false
$serviceGroups = Get-NetScalerWhiteList
$ValidateSetAtrribute = New-Object System.Management.Automation.ValidateSetAttribute($serviceGroups)
$AttributeCollection.Add($ValidateSetAtrribute)
$AttributeCollection.Add($ParameterAttribute)
$RunTimeParameter = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)
$RuntimeParameterDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary
$RuntimeParameterDictionary.Add($ParameterName, $RunTimeParameter)
$RuntimeParameterDictionary
}
Begin
{
$ServiceGroup = $PSBoundParameters[$ParameterName]
}
Process
{
Copy-Item "$masterIgnoreFilePath\ingnore.txt" "$masterIgnoreFilePath\ingnore.bak"
$serviceGroups = Get-NetScalerWhiteList
$serviceGroups.Remove($serviceGroup)
Write-Host $serviceGroups
}
}