Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Friday, December 9, 2016

Auto Populating a Parameters’ Value from a Dynamic List

First off, I want to give a shout out to Author: Martin Schvartzman and his blog posting

A question that I often get when teaching parameter validation is "can you load the values of a parameter dynamically?" Up until now, my answer was no.  Time to change that.  After getting that question again, I did some more research and found Martin’s article.  Simply adjusting 1 line of the code from his blog posting allowed me to load the SamAccountNames of all users in the domain as the valid, and TAB complete capable, values of a parameter.  Below is that code:

# Author: Martin Schvartzman
# Minor modifications: Jason Yoder

function Test-DynamicValidateSet {
        # Any other parameters can go here

    DynamicParam {
            # Set the dynamic parameters' name
            $ParameterName = 'User'
            # 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

            # Generate and set the ValidateSet.
            # Change the next line to produce what you want to auto populate for the parameter.
            # Make sure it is DataType String.
            $arrSet = Get-ADUser -Filter * | Select-Object -ExpandProperty SamAccountName
            $ValidateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute($arrSet)

            # Add the ValidateSet to the attributes collection

            # 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
        $User = $PsBoundParameters[$ParameterName]

    process {
        # Your code goes here
        Get-ADUser -Identity $USer


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