Parameter attributes (Mandatory, ValidateSet) in PowerShell - Mini Project: Build & Apply

Using Parameter Attributes: Mandatory and ValidateSet in PowerShell

📖 Scenario: You are creating a PowerShell script to manage user roles in a small company. The script will accept a username and a role to assign. To avoid errors, you want to make sure the username is always provided and the role is one of the allowed options.

🎯 Goal: Build a PowerShell script that uses parameter attributes Mandatory and ValidateSet to ensure the user inputs a username and selects a valid role from a predefined list.

📋 What You'll Learn

Create a function called Set-UserRole with parameters Username and Role.

Make the Username parameter mandatory.

Restrict the Role parameter to only accept Admin, User, or Guest using ValidateSet.

Print a confirmation message showing the username and assigned role.

💡 Why This Matters

🌍 Real World

Scripts often need to ensure users provide required information and select valid options to avoid mistakes.

💼 Career

Knowing how to enforce parameter rules helps create reliable and user-friendly automation scripts in IT and DevOps roles.

1

Create the function with parameters

Write a PowerShell function named Set-UserRole with two parameters: Username and Role. Do not add any attributes yet.

PowerShell

function Set-UserRole {
    param(
        $Username,
        $Role
    )
    # Your code here
}

Need a hint?

Define the function and list the parameters inside param().

2

Make the Username parameter mandatory

Add the [Parameter(Mandatory=$true)] attribute to the Username parameter inside the param() block.

PowerShell

function Set-UserRole {
    param(
        # Add Mandatory attribute to Username
        $Username,
        $Role
    )
}

Need a hint?

Use [Parameter(Mandatory=$true)] just before $Username.

3

Restrict Role parameter with ValidateSet

Add the [ValidateSet('Admin','User','Guest')] attribute to the Role parameter inside the param() block.

PowerShell

function Set-UserRole {
    param(
        [Parameter(Mandatory=$true)]
        $Username,
        # Add ValidateSet attribute to Role
        $Role
    )
}

Need a hint?

Use [ValidateSet('Admin','User','Guest')] just before $Role.

4

Print confirmation message

Inside the function body, add a Write-Host statement that prints: "User <Username> assigned role <Role>" using the parameters.

PowerShell

function Set-UserRole {
    param(
        [Parameter(Mandatory=$true)]
        $Username,
        [ValidateSet('Admin','User','Guest')]
        $Role
    )
    # Print confirmation message
}

Need a hint?

Use Write-Host "User $Username assigned role $Role" inside the function.