Using dynamic parameters value in PowerShell

Question

I am trying to use a dynamic parameter in PowerShell, but the value for the parameter doesn\'t seem to exist after I have run through my script.

[CmdletBindi         


        

Answer 1

Here's how I tried using dynamic parameters to get Configuration Manager logs.

Credit goes to the blog post here.

Usage: Get-CCMLogs -ComputerNames -Remote -RemoteLogName <Tab to complete lognames>

Local usage: Get-CCMLogs -ComputerNames -LocalLogName <Tab to complete lognames>

The dynamic parameter will return a remote log name if the switch -Remote is entered or return a local log name if the switch -Remote is not entered.

Function Get-CCMLogs {

    [CmdletBinding()]

    Param(
        [Parameter(Mandatory=$false,
            ValueFromPipeline=$true,
            ValueFromPipelineByPropertyName=$true,
            HelpMessage="Give me a list of computer names!")]
        [Alias('Hostname','cn')]
        [string[]]$ComputerNames = $env:COMPUTERNAME,

        [switch]$Remote
    )

    DynamicParam{

        If ($Remote) {

            $ParameterName = 'RemoteLogName'

            $RunTimeDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary

            $AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]

            $ParamAttribute = New-Object System.Management.Automation.ParameterAttribute
            $ParamAttribute.Mandatory = $true
            $ParamAttribute.Position = 1

            $AttributeCollection.Add($ParamAttribute)

            $ValidateItems = Get-ChildItem -Path "\\$ComputerNames\C$\Windows\CCM\Logs" | Where {$_ -notmatch '\d+'} | Select -ExpandProperty FullName
            $ValidateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute($ValidateItems)

            $AttributeCollection.Add($ValidateSetAttribute)

            $RunTimeParam = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)

            $RunTimeDictionary.Add($ParameterName, $RunTimeParam)

            Return $RunTimeDictionary
        }
        else {
            $ParameterName = 'LocalLogName'

            $RunTimeDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary

            $AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]

            $ParamAttribute = New-Object System.Management.Automation.ParameterAttribute
            $ParamAttribute.Mandatory = $true
            $ParamAttribute.Position = 1

            $AttributeCollection.Add($ParamAttribute)

            $ValidateItems = Get-ChildItem -Path C:\Windows\CCM\Logs | Select -ExpandProperty FullName | Where {$_ -notmatch '\d+'}
            $ValidateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute($ValidateItems)

            $AttributeCollection.Add($ValidateSetAttribute)

            $RunTimeParam = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)

            $RunTimeDictionary.Add($ParameterName, $RunTimeParam)

            Return $RunTimeDictionary
        }
    }

    Begin{
        $LogName = $PSBoundParameters[$ParameterName]
    }

    Process{
        cmtrace.exe $LogName
    }
}