Dynamic Parameter Example

function Restart-RemoteService {
   [CmdletBinding()]
   Param ($ComputerName = $env:COMPUTERNAME)
   DynamicParam {

      # Set the dynamic parameters' name
      $ParameterName = 'Service'

      # Create the dictionary
      $RuntimeParameterDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary

      # Create the collection of attributes
      $AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]

      # Create and set the parameters' attributes
      $ParameterAttribute = New-Object System.Management.Automation.ParameterAttribute
      $ParameterAttribute.Mandatory = $true
      $ParameterAttribute.Position = 1

      # Add the attributes to the attributes collection
      $AttributeCollection.Add($ParameterAttribute)

      # Generate and set the ValidateSet
      $arrSet = Get-WmiObject Win32_Service -ComputerName $computername | select -ExpandProperty Name
      $ValidateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute($arrSet)

      # Add the ValidateSet to the attributes collection
      $AttributeCollection.Add($ValidateSetAttribute)

      # Create and return the dynamic parameter
      $RuntimeParameter = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)
      $RuntimeParameterDictionary.Add($ParameterName, $RuntimeParameter)
      return $RuntimeParameterDictionary
   }

   begin {
      # Bind the parameter to a friendly variable
      $Service = $PsBoundParameters[$ParameterName]
   }

   process {
      Write-Debug 'ham'
      ForEach ($machine in $computername) {
         write-host "Stopping service $service on host $machine..." -NoNewline
         Get-WmiObject -ClassName Win32_Service -ComputerName $machine | Where Name -eq $service | % StopService | Out-Null
         write-host "[OK]" -ForegroundColor Cyan

         Write-Host "Starting Service $service on host $machine..." -NoNewline
         Get-WmiObject -ClassName Win32_Service -ComputerName $machine | Where Name -eq $service | % StartService | Out-Null
         write-host "[OK]" -ForegroundColor Cyan
      }
   }

}