DynamicParameters.ps1

function Create-Parameters{
  param([scriptblock]$Params)    
  $runtimeParameterDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary
	$parameters = & $Params
	foreach($parameter in $parameters)
	{
		$runtimeParameterDictionary.Add($parameter.Name, $parameter)
	}    
  $runtimeParameterDictionary
}

function New-Parameter{
    param($Name, $Position, $ValidateSet, $Mandatory=$false)		
    $attributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]
    $parameterAttribute = New-Object System.Management.Automation.ParameterAttribute
    $parameterAttribute.Mandatory = $Mandatory
    $parameterAttribute.Position = $Position
    $attributeCollection.Add($parameterAttribute)   
    $validateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute -ArgumentList $ValidateSet
    $attributeCollection.Add($validateSetAttribute)
    New-Object System.Management.Automation.RuntimeDefinedParameter($Name, [string], $attributeCollection)
}

function Kill-Service{    
    DynamicParam{
       Create-Parameters -Params {            
            New-Parameter -Name "Service" -Position 0 -Mandatory $true -ValidateSet $(Get-Service | Select-Object -ExpandProperty Name)        
       }
    }
    process{
       Get-Service -Name $PsBoundParameters["Service"] | kill
    }
}